In an extraordinarily blunt intervention, Air Chief Marshal Sir Richard Knighton warned that Russia's military strength is increasing and is something to fear, with Russian troops now battle-hardened after spending the past nearly four years waging a full-scale war in Ukraine.
He said the UK's armed forces would always be the first line of defence alongside the rest of the NATO alliance, but the whole of society must also play a part in rebuilding resilience.
The chief of the defence staff said it is important to be honest with "families and households" across the UK about what it means to be prepared for "an array of real, physical threats".
Serving up a sombre reality check, Air Chief Marshal Knighton said he agreed with his French counterpart, General Fabien Mandon, who said last month that France must be ready for the possibility of losing its children in a potential war with Russia.
"The situation is more dangerous than I have known during my career, and the price of peace is rising," the British defence chief said.
"Our response needs to go beyond simply strengthening our armed forces. It needs a whole of nation response that builds our defence industrial capacity, grows the skills we need, harnesses the power of the institutions we will need in wartime and ensures and increases the resilience of society and the infrastructure that supports it."
He continued: "Sons and daughters. Colleagues. Veterans. …will all have a role to play.
"To build. To serve. And if necessary, to fight. And more families will know what sacrifice for our nation means."
Most people in the UK, though, no longer have direct experience of the armed forces thanks to the peace that followed the end of the Cold War almost 35 years ago.
The military chief noted that it was 65 years ago this month since the last national service call-ups took place, and 80 years since the end of the Second World War.
But he indicated that the kind of national defence and resilience that was once second nature to UK society up until the collapse of the Soviet Union needs to return.
He said that while there was only deemed by defence analysts to be a "remote" chance of up to a 5% of Russia launching a "significant direct attack or invasion" against the UK, this "does not mean the chances are zero".
Air Chief Marshal Knighton said: "My point is that none of us can say with any certainty what the absolute risk might be. And even though simple binary statements might be easy for people to engage with, they risk instilling panic or complacency.
"What really matters is the trend. Are the chances of conflict growing?
"And here, I think the evidence is clear that the trend, from Russia in particular, is worsening, and that is the key argument for action."
Turning to the capability of the Russian armed forces, despite being locked in a major war against Ukraine, he said their "hard power is growing quickly".
"Over the past 20 years, Russia has delivered significant defence reform and investment into what were weak and hollowed-out armed forces," he said.
"The Russian armed forces are now more than 1.1 million strong, consuming more than seven per cent of GDP, and around 40 per cent of government spending, which is a sum that has more than doubled over the past decade."
By contrast, the UK army is a little over 70,000 soldiers, with the government only committed to increasing defence spending to 2.5% of GDP from 2.3% by 2027.
"We should be under no illusions that Russia has a massive, increasingly technically sophisticated, and now, highly combat-experienced, military," the military chief said.
He described how Russia is "developing new and destabilising weapons systems such as nuclear-armed torpedoes and nuclear-powered cruise missiles putting nuclear weapons in space. So it is absolutely clear that Russia's hard power is something to fear, but what about Russia's intent to use it?"
The military chief said the war in Ukraine and Russia's willingness to target its neighbouring states show it "wishes to challenge, limit, divide and ultimately destroy NATO".
But he acknowledged this threat is not yet felt in the UK as it is in countries that share physical land borders with Russia.
In a sign that he is seeking a more rapid increase in defence spending, he said Germany expects to spend 3.5% of GDP on defence by 2029, while Poland is already at 4.2%.
"And we have seen just in the past few weeks France and Germany return to a form of national service."
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He continued: "In reality, other than proximity, the threat in the UK isn't really any different to the threat in Germany, for example.
"Unless we are able to raise awareness and stimulate the conversation with society about the risks, we can't expect the rest of government, society and industry to act or bear the costs."
The defence chief called out a podcast series by Sky News and Tortoise called The Wargame, which simulates a Russian attack on the UK, as an example of efforts in the media to raise public awareness.
Building on the success of the highly acclaimed podcast The Wargame, Sky News presents The Wargame: Decoded - a one-off live event that takes you deep inside the minds of the wargame's participants. Discover how they tackled the toughest challenges, the decisions they made under intense pressure, and even experience key moments of the game for yourself.
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Sky News' Deborah Haynes will guide the conversation with Sir Ben Wallace, Robert Johnson, Jack Straw, Amber Rudd, Keir Giles and General Sir Richard Barrons - real-life military chiefs, former government officials and leading experts. Together, they will unpack their experiences inside The Wargame, revealing the uncertainty, moral dilemmas and real-world pressures faced by those who must make decisions when the nation is under threat.
Join us for this unique event exploring how the UK might respond in a moment of national crisis and get a rare, unfiltered glimpse into how prepared the country truly is for war.
The US president said in a post on Truth Social that Reiner was "a tortured and struggling, but once very talented movie director and comedy star".
Mr Trump said Reiner and his wife died "reportedly due to the anger he caused others through his massive, unyielding, and incurable affliction with a mind crippling disease known as TRUMP DERANGEMENT SYNDROME, sometimes referred to as TDS".
"He was known to have driven people CRAZY by his raging obsession of President Donald J. Trump, with his obvious paranoia reaching new heights as the Trump Administration surpassed all goals and expectations of greatness, and with the Golden Age of America upon us, perhaps like never before. May Rob and Michele rest in peace," Mr Trump wrote.
Celebrities and politicians have criticised Mr Trump for his comments, labelling them "disgusting" and "petty".
"What a disgusting and vile statement," actor Patrick Schwarzenegger said on X, while Californian Democrat Zoe Lofgren condemned Mr Trump's comments as "a new low for this petty, hateful man".
Talk show host Whoopi Goldberg compared the president's comments to those he made after the assassination of right-wing activist Charlie Kirk, when Mr Trump hit out at critics.
"I don't understand the man in the White House. He spoke at length about Charlie Kirk and about caring, and then this is what he puts out. Have you no shame? No shame at all? Can you get any lower? I don't think so," she said.
"This is a sick man," California governor Gavin Newsom wrote on X.
Republican US House member Thomas Massie also addressed the comments, saying: "Regardless of how you felt about Rob Reiner, this is inappropriate and disrespectful discourse about a man who was just brutally murdered."
Meanwhile, Reiner's son, Nick, 32, has been "booked for murder", Los Angeles police chief Jim McDonnell said. The LAPD later said Nick Reiner remains in custody without bail.
Mr McDonnell said the department's robbery and homicide division was handling the investigation.
"They worked throughout the night on this case and were able to take into custody Nick Reiner, a suspect in this case," he said, calling the deaths "a very tragic incident".
It comes as it emerged Nick was reportedly disruptive when he joined his father and mother, Michele Singer Reiner, at a party hosted by comedian Conan O'Brien on Saturday night, the day before the killings.
Reiner and his wife were upset and embarrassed about their son's behaviour, Sky News's US partner NBC News cited a source as saying, and expressed concerns about his health.
The outlet cited another source saying Nick's behaviour had made other guests uncomfortable. They said he interrupted a conversation comedian and filmmaker Bill Hader was having with two guests and, when told it was a private conversation, stood still and stared before storming off.
Reiner and his wife apparently died of stab wounds, US media reported.
The Los Angeles Fire Department said a 78-year-old man and a 68-year-old woman were found dead inside a property in the Brentwood neighbourhood, without identifying the victims. The victims were later confirmed to be Reiner and his wife.
The case against Nick Reiner will be presented to the Los Angeles county district attorney's office for filing consideration on Tuesday, according to the LAPD.
Nick Reiner has spoken publicly of his struggles with addiction after he had cycled in and out of treatment facilities by the age of 18, with periods of homelessness and relapses in between.
Reiner and his son explored their difficult relationship and Nick Reiner's struggles with heroin addiction and homelessness in a 2016 film called Being Charlie, which they co-wrote.
Republican congresswoman Marjorie Taylor Greene referred to Nick Reiner's "drug addiction and other issues" in a statement on X.
"This is a family tragedy, not about politics or political enemies," Ms Taylor Greene said.
"Many families deal with a family member with drug addiction and mental health issues. It's incredibly difficult and should be met with empathy especially when it ends in murder."
Reiner was a celebrated director whose work included some of the most memorable movies of the 1980s and 1990s.
He directed classics such as This Is Spinal Tap, The Princess Bride, When Harry Met Sally, A Few Good Men and Stand By Me.
He also acted, starring in Sleepless In Seattle and The Wolf Of Wall Street among others. His most recent high-profile work was a recurring guest role in the hit show The Bear.
He met Michele Singer in 1989, while directing When Harry Met Sally. They have three children together.
Singer used to work as a photographer and took the photo of Donald Trump that appears on the cover of his book Trump: The Art Of The Deal.
Former US president Barack Obama has led tributes. He wrote on X that "Michelle and I are heartbroken by the tragic passing of Rob Reiner and his beloved wife, Michele. Rob's achievements in film and television gave us some of our most cherished stories on screen".
Harry Shearer, who collaborated with Reiner on This Is Spinal Tap, said in a statement: "Rob was a friend and collaborator through much of my life. He was funny, he was smart, he was a mensch."
He said Reiner's wife was a "very good friend" to his own wife, Judith, adding: "This is unspeakable, the stuff of Greek tragedy."
Christopher Guest, who starred in Reiner's films This Is Spinal Tap and The Princess Bride, and his wife Jamie Lee Curtis said in a joint statement that they were "numb and sad and shocked about the violent, tragic deaths of our dear friends Rob and Michelle Singer Reiner".
The couple said: "There will be plenty of time later to discuss the creative lives we shared and the great political and social impact they both had on the entertainment industry, early childhood development, the fight for gay marriage and their global care for a world in crisis. We have lost great friends. Please give us time to grieve."
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Reiner was a champion of liberal causes and a political activist.
In the 2004 presidential election, he backed Democrat candidate John Kerry and featured in advertisements taking aim at incumbent president George W Bush.
Reiner also supported Democratic presidential hopefuls Al Gore and Hillary Clinton.
"This is a devastating loss for our city and our country. Rob Reiner's contributions reverberate throughout American culture and society, and he has improved countless lives through his creative work and advocacy fighting for social and economic justice," Los Angeles mayor Karen Bass said.
California governor Mr Newsom paid tribute to Reiner's activism as he said he was "heartbroken" over the director's death.
"Rob was a passionate advocate for children and for civil rights - from taking on Big Tobacco, fighting for marriage equality, to serving as a powerful voice in early education," Mr Newsom said in a statement.
"He made California a better place through his good works. Rob will be remembered for his remarkable filmography and for his extraordinary contribution to humanity."
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Former House speaker, Democrat Nancy Pelosi, said: "Personally, Rob cared deeply about people and demonstrated that in his civic activities - whether by supporting the First 5 initiative or fighting against Prop 8 in California.
"Civically, he was a champion for the First Amendment and the creative rights of artists. And professionally, he was an iconic figure in film who made us laugh, cry and think with the movies he created."
Doyle, who used a car as a "weapon" to plough through more than 100 people celebrating Liverpool's Premier League title win, told officers "I've just ruined my family's life", the court heard.
The sentencing hearing was told the 54-year-old was "in a rage" and his "anger had completely taken hold of him".
Doyle is due to be sentenced on Tuesday after pleading guilty to 31 offences relating to seriously injuring people during the victory parade on 26 May.
Doyle, described as a "family man" by prosecutors, wept as footage of the horrific rampage was shown to the city's crown court several times on Monday.
Paul Greaney KC, prosecuting, described the actions of Daniel Barr, who he called the "hero" of the day.
Mr Barr, an ex-soldier, had "bravely" jumped into the back of Doyle's Ford Galaxy and placed the vehicle into park.
He was walking up Water Street when he noted the defendant's Ford Galaxy in the distance, said Mr Greaney, noting the crowd's attitude changed from "joyous to desperate".
Doyle's vehicle then stopped next to Mr Barr "all of a sudden".
"Daniel Barr instinctively pulled open the rear passenger-side door and climbed in. He did so with the intention of stopping the driver," the prosecutor said.
Mr Barr leaned forward and moved the gear into "park" and "held it as hard as he could".
Mr Greaney added: "The Galaxy did not stop immediately, but in the end it did."
The prosecutor said police officers forced Doyle into a police van after the attack.
This, he said, was done "in the midst of a hostile crowd", adding that officers' behaviour was both "brave and effective".
When Doyle was securely in the van, Mr Greaney said police body-worn camera footage picked up him saying: "I've just ruined my family's life."
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Doyle admitted dangerous driving, affray, 17 charges of attempting to cause grievous bodily harm (GBH) with intent, nine counts of causing GBH with intent, and three counts of wounding with intent last month.
He had previously denied the offences, which relate to 29 victims aged between six months old and 77 years old.
The court was shown dashcam footage taken from the defendant's car showing the attack.
Mr Greaney warned the court: "What we are about to display on the screens is truly shocking."
There were audible gasps in the courtroom as the footage played.
Doyle could be heard repeatedly shouting at pedestrians to "move out the f****** way" as he drove through crowds.
Consistently using his vehicle's horn, people could be seen trying to jump out of the way, with some forced on to the bonnet of the car.
"F****** pr****," Doyle shouts as the footage continues.
By the end of the footage, people begin to attempt to run up to the vehicle.
When the car stops, one man shouts, "get the f*** out of the car".
Mr Greaney also detailed some of the injuries sustained by victims on the day of the attack.
One woman, aged 66, spent four nights in hospital after breaking six ribs and suffering fractures to her fingers on her left hand and her left wrist.
Another woman, aged 77 at the time, spent 27 days in hospital.
The prosecutor said she suffered a fractured left forearm, fractured left collar bone, three fractured ribs, a fractured pelvis, a broken nose, as well as multiple abrasions and bruising to her head, knees and back.
Another victim, who was 17, suffered bruising to their legs, shoulder and had a small fracture to their tibia.
After suffering wound infections, it took two months before the victim regained mobility, the prosecutor added.
Mr Greaney said some people at the scene on 26 May "thought that what was taking place was a terrorist attack".
However, the prosecution ruled out that the defendant's actions were "driven by ideology".
Police investigations showed there was no problem with the vehicle, and Doyle was completely sober and "free of all drugs", Mr Greaney said.
"The truth is a simple one - Paul Doyle just lost his temper in his desire to get to where he wanted to get to.
"In a rage, he drove into the crowd," he added.
Doyle was arrested at the scene in Water Street just after 6pm and charged later that week.
The youngest victim was six-month-old Teddy Eveson, whose parents later told media he was thrown about 15ft down the road in his pram when the crash happened.
Doyle, of Croxteth, Liverpool, admitted attempting to cause grievous bodily harm to the baby.
Five other children, whom Doyle either injured or attempted to injure, cannot be named for legal reasons.
Federal authorities in the US said the four are allegedly part of an extremist group which is suspected of planning the attacks in southern California.
The plot consisted of planting explosive devices at five locations targeting two US companies at midnight on New Year's Eve in the Los Angeles area.
The suspects were arrested last week in Lucerne Valley, a desert city east of Los Angeles.
They are said to be members of an offshoot of a pro-Palestinian, anti-government and anti-capitalist group dubbed the Turtle Island Liberation Front, the complaint said.
As well as the alleged plan against the two companies, the group also planned to target Immigration and Customs Enforcement (ICE) agents and vehicles, attorney general Pam Bondi said.
The four defendants named in the complaint are Audrey Illeene Carroll, 30, Zachary Aaron Page, 32, Dante Gaffield, 24 and Tina Lai, 41.
All four are from the Los Angeles area, according to first assistant US attorney Bill Essayli.
The alleged plot
According to a sworn statement in support of the complaint, Carroll showed an eight-page handwritten document to a paid confidential source in November, which described a bomb plot.
The document was titled "Operation Midnight Sun".
Essayli said one of the suspects created a detailed plan that "included step-by-step instructions to build IEDs (improvised explosive devices)… and listed multiple targets across Orange County and Los Angeles."
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Carroll and Page are then alleged to have recruited the other two defendants to help them carry out the plan which included acquiring bomb-making materials before constructing and performing test detonations.
Under the plan, the defendants would supposedly have travelled to a remote location in the Mojave Desert on 12 December to construct and detonate their test explosive devices, the sworn statement alleges.
Evidence photos included in the court documents show a desert campsite with what investigators said were bomb-making materials strewn across plastic folding tables.
The FBI said agents intervened before the defendants could complete their work to assemble a functional explosive device.
The Met Office said "15-25mm of rain is likely to accumulate quite widely" in South Wales and the South West of England on Wednesday and will fall on ground which is already saturated.
The yellow warning applies from 10am until the end of the day.
Check the forecast for your area
There is a chance of power cuts and disruption to travel networks, while some communities could "become cut off" due to the conditions, said the Met Office.
It comes as many parts of the UK were already facing warnings previously issued for Monday and Tuesday.
An amber rain warning for possible danger to life is in force until 9pm on Monday for southern parts of Wales.
Forecasters said 50mm to 80mm of rain is "likely to fall quite widely" with some places "seeing close to 100mm".
The Met Office added that "fast flowing or deep floodwater is likely, causing danger to life" and warned it was "not safe to drive, walk or swim" through such conditions.
"Given the recent wet weather and saturated ground, the likelihood of impacts is higher," the agency said.
"If you must travel, ensure you watch for possible danger and drive cautiously."
Further yellow rain warnings are also currently in place for parts of northeast, northwest and southwest England, the East Midlands, the West Midlands and Wales.
Most apply for much of Monday, but the warning for the North East of England and Yorkshire is in force until 3am on Tuesday.
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Sky News meteorologist Dr Christopher England said the "prolonged heavy rain on already saturated ground" has led to the series of Met Office warnings.
"In Cumbria, there has been over 150mm of rain quite widely, with 360.6mm recorded at the Honister Pass - over a foot in old money - while Scotland has seen over 100mm in places," he said.
"Further rain moving in on Wednesday has led to another yellow warning in the South West, indicating the chance of some significant disruption there."
It comes after the UK faced a series of similar warnings at the weekend.