The flight to evacuate Britons stuck in the region due to the Iran war was scheduled to depart Muscat in Oman at 11pm local time on Wednesday.
However, it never took off and the passenger said they had been told the pilot needed to rest.
Follow live updates on the Middle East crisis
The Briton - who wanted to stay anonymous - told Sky News: "[The] check-in process took about four hours due to technical issues. We then got taken to the plane on a bus but had to stay on it for about one-and-a-half hours.
"No consular staff were present airside. They just left us. People started getting very agitated, banging windows, panic attacks.
"There are dozens and dozens of vulnerable people, young children and families."
A Foreign Office spokesperson said: "The UK government charter flight was not able to depart from Oman yesterday as planned due to technical issues. The flight is now expected to depart later today."
People who were due on the flight were taken back to a hotel.
The passenger told Sky News they had been told that "due to slow check-in and delays, the pilot had clocked his hours so needed to rest".
"We have been told the plane will take off later today [Thursday] once the pilot has rested," they added.
"The stress this has caused these vulnerable people is incredibly serious."
Border security minister Alex Norris told Sky's Sophy Ridge on Mornings: "There have been a number of commercial flights that have gone yesterday. We have chartered a flight out of Oman that wasn't able to leave last night for operational reasons.
"We expect that to be leaving today, we expect there to be multiple more flights following that.
"So I know people are feeling stressed; our people are on the ground, including at the airport, are helping them support them through that.
"We've helped them make sure they've found hotel rooms that we paid for to support them through that process."
Mr Norris added: "I know it's frustrating, but these things obviously are fast moving and do take a little time to stand up."
Planes chartered by other European governments have already brought home some of their citizens.
A German Lufthansa plane from Oman landed in Frankfurt early this morning, while Spanish and Italian flights have also made it home.
BA and Emirates flights land in UK
Air traffic in the Middle East has been thrown into chaos by Iran firing drones and missiles at US bases in the region in retaliation for attacks on its country.
However, a small number of commercial flights are now operating and the prime minister said on Wednesday that more than 1,000 Britons had managed to get home.
Read more from Sky News:
Stranded in the Middle East? What you need to know
British Airways is among those that have been able to restart a few services back to the UK. Its flight from Muscat in Oman landed at Heathrow shortly after 8am on Thursday.
Emirates flights from Dubai also arrived at Heathrow and Manchester this morning.
Muscat, which has been largely unaffected by the conflict so far, has emerged as a key location for people trying to leave the Middle East.
It can be reached by road from both Dubai and Abu Dhabi with journeys of about 300 miles (482km).
Food and drink giant Nestle recalled dozens of batches of its SMA infant formula and follow-on formula in January.
The recall, which has affected more than 60 countries, was sparked by concerns about the presence of cereulide, a heat-resistant toxin that can cause symptoms such as vomiting, diarrhoea and stomach cramps.
Danone has also recalled batches of Aptamil and Cow & Gate first infant milk, citing the same contamination concerns.
See the list of recalled products
The UKHSA said it is looking into cases from across the UK where children have fallen ill with symptoms "consistent with cereulide toxin poisoning".
Investigators said 35 of the babies were male and 26 were female.
Confirmed infections due to other seasonal viruses were only noted in "some" of the children, said the UKHSA.
Since the first Nestle recall in early January, Sky News has spoken with several families who unknowingly fed their babies from affected batches.
Chloe Fernandes's eight-month-old daughter Rebecca needed hospital treatment after being fed a now-recalled batch of prescription-only SMA formula.
"Rebecca became very ill mid-December," Ms Fernandes, from Nottinghamshire, told Sky News.
"She had horrific diarrhoea and severe vomiting which led to her choking and needing to go to hospital."
Her daughter was treated for dehydration and has since fully recovered.
Ms Fernandes added: "All parents need answers. It was a horrific experience."
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The UKHSA confirmed that toxin was introduced into the formula via an ingredient, an oil, produced by a third-party supplier and shared by both Nestle and Danone.
"Testing of the recalled formula has confirmed presence of the toxin in some batches at levels that exceed limits set by the European Food Safety Authority and therefore pose a potential health risk," said Gauri Godbole, the UKHSA's deputy director of gastrointestinal infections.
She added: "Parents and caregivers are advised to recheck and remove all recalled formula from their homes to prevent illness in their children."
Sky News has contacted Danone and Nestle for comment.
Former Royal Marine Alun Harris-Richards, 61, suffered a fatal heart attack while trying to prevent Natasha Smith, 38, from leaving the premises and fell to the ground, where he struck his head.
At the High Court in Edinburgh in January, Smith pleaded guilty to culpable homicide and assaulting another Asda employee during the same altercation.
She was sentenced on Thursday.
Lady Haldane said on the day in question, Smith "set in train a series of events that ultimately had devastating consequences for Alun Harris-Richards, his family and all who knew and loved him".
The judge added: "Mr Harris-Richards lost his life that day when he was simply doing his job as a security guard in a supermarket."
Following Mr Harris-Richards' death, a post-mortem examination found he had a coronary artery condition.
Pathologists reported that people with the condition are "at risk of sudden death at any time" and this is particularly true in times of illness or stress.
The incident occurred at the supermarket in Arbroath's Westway Retail Park, Angus, on 30 June 2024.
The court heard that during the confrontation, which was recorded on Mr Harris-Richards' body-worn camera, Smith shouted, swore, falsely accused her victim of assaulting her, and repeatedly attempted to pull a bag containing the alcohol from his grasp.
In footage shown to the court, Smith screamed "you're not allowed to touch me", "get your f****** hands off me" and "who do you think you are, f****** Hulk?"
Repeat offender Smith said she planned to sell the alcohol to a pub.
After Mr Harris-Richards fell to the ground, Smith continued to struggle with two female employees and grabbed one of them, put her hands around her neck and threatened: "I will end you."
The woman was also punched in the face and had her hair pulled during the assault.
Advocate depute Adrian Stalker previously told the court that shortly before the struggle, Smith was seen in the spirits aisle at the supermarket and a staff member became suspicious that she might be shoplifting.
Smith went to the self-service checkout area carrying a can of alcohol and bags, but then went towards the exit, triggering alarms.
Mr Harris-Richards and another staff member intercepted her and took hold of a reusable bag she was carrying containing two bottles, but Smith would not let it go.
During the confrontation, Mr Harris-Richards' breathing became laboured and he fell to the floor.
Mr Stalker said: "He was immediately unresponsive.
"The deceased received first aid, CPR and emergency medical treatment from staff, customers and paramedics where he had fallen. These efforts were to no avail."
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Lady Haldane said she had received moving victim impact statements from members of Mr Harris-Richards' family.
She added: "It is clear Mr Harris-Richards was a much-loved member of the family who was deeply involved with his children and grandchildren."
A background report prepared on Smith showed that she had suffered trauma in her own life and significant adverse experiences in childhood.
Defence solicitor advocate Kris Gilmartin said his client felt "deep remorse" for her actions that led to the death.
He said that at the time of the killing she was "in the throes of drug and alcohol abuse" and footage of the events showed her desperation to keep a hold of the bag and its contents.
Mr Gilmartin said she did not intend to cause Mr Harris-Richards harm, but has to live with the fact that her actions brought about his death.
He said she was haunted by nightmares of the incident.
Moira Orr, who leads on homicide for the Crown Office and Procurator Fiscal Service (COPFS), said: "This was an unprovoked attack on a man who was simply doing his job.
"Natasha Smith's actions resulted in tragic consequences and robbed a much-loved family man of his life.
"Our thoughts lie with Mr Harris-Richards' family and friends. We are sorry for their loss."
Joani Reid, who was elected in East Kilbride and Strathaven at the last general election, issued a statement after the Metropolitan Police announced three arrests on Wednesday morning as part of a counter-terrorism investigation under the National Security Act.
The force did not name the suspects - all men, aged 39, 43, and 68 - but one of them is her husband, David Taylor.
They have all been released on bail, the Met Police said on Thursday morning.
Ms Reid said: "I have never seen anything to make me suspect my husband has broken any law.
"I am not part of my husband's business activities, and neither I nor my children are part of this investigation, and we should not be treated by media organisations as though we are.
"Above all I expect media organisations to respect my children's privacy."
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She also said she had never been to China, never spoken about the country or its regime in parliament, and also never knowingly met any Chinese businesses, diplomats, or government employees while serving as an MP.
"I am not any sort of admirer or apologist for the Chinese Communist Party's dictatorship," she added.
Ms Reid is the granddaughter of trade unionist Jimmy Reid and served as a councillor in Lewisham, south London, for eight years before becoming an MP.
Her husband is listed on the MP's register of interests as a director of Earthcott Limited, a lobbying firm.
Government 'deeply concerned'
Security minister Dan Jarvis made a statement in the Commons following news of the arrests.
He told MPs the government - which has sought to forge closer economic ties with China - is "deeply concerned by an increasing pattern of covert activity from Chinese state-linked actors targeting UK democracy".
"If there is proven evidence of attempts by China to interfere with UK sovereign affairs, we will impose severe consequences and hold all actors involved to account," he added.
Tories question Labour's China approach
Prime Minister Sir Keir Starmer visited Beijing earlier this year and planning permission has been granted for a controversial "super embassy" in London.
Mr Jarvis told MPs "it continues to be in our long-term strategic interests to engage with China".
But the Conservatives accused Labour of pursuing a "failed policy of appeasement".
Shadow cabinet minister Alex Burghart called for the Chinese ambassador to the UK to be summoned and told interference "will no longer be tolerated".
He also said China should be placed on the highest tier of the government's Foreign Influence Registration Scheme.
The fine relates to the water company's supply interruptions in Kent and Sussex between 2020 and 2023, which affected more than 286,000 people. It is also under investigation for outages over the last four months.
Ofwat said the fine "reflects the severity of the issues". A consultation is open to the public and shareholders until 13 April, before the watchdog confirms its final decision.
Chris Walters, interim CEO at Ofwat, said: "South East Water's significant failings caused major disruption and had a huge impact on thousands of its customers.
"Not only did the company fail in its duty to provide a water supply to meet the demands of its customers, but it also fell short when it came to providing support for customers who lost their supply. They must do better.
"This investigation gets to the heart of the company's supply resilience problems. We want to see South East Water take more responsibility and get on with fixing things for its customers."
A spokesperson for South East Water said the company sought an injunction, and that it is "now considering Ofwat's draft decision and will respond via the appropriate channels, ahead of its final decision".
SEW 'failed' to learn from Beast from the East
In a statement, Ofwat said an investigation found that South East Water "failed to plan sufficiently, learn from incidents and conduct root cause analysis to maintain resilience within its water supply system, and was therefore unable to cope during periods of high demand or extreme weather".
It added that the company "failed to maintain key infrastructure such as service reservoirs, boreholes and major pipes" which the watchdog said "left the system more likely to fail during prolonged dry periods or freeze thaw events".
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"As a result of the disruptions, customers had no tap water, were unable to shower or bathe, and unable to flush their toilets, which caused immense stress and anxiety," Ofwat said.
"Ofwat's investigation found that the company's response was slow and disorganised, with shortages of bottled water and not enough tankers or support for vulnerable customers.
"It also failed to learn lessons from previous incidents, including the Beast from the East in 2018."
A report from Ofwat at the time of the snowstorm found households and businesses were badly let down by some water firms.
More than 200,000 customers in England and Wales were left without supplies for more than four hours, while over 60,000 customers did not have a water supply for more than 12 hours.
Environment Secretary Emma Reynolds said water supply disruptions "are wholly unacceptable".
"It is entirely right Ofwat is holding South East Water to account... reliable water supplies are not optional. Water companies must prioritise their customers, and deliver the services people deserve."
Mike Keil, chief executive of the Consumer Council for Water (CCW), said: "People across Kent and Sussex will rightly want to know whether this fine will make any difference to the reliability of the services they receive from the company.
"Customers are fed up of living with the worry and uncertainty of not knowing whether their taps will run dry every time there is a change in the weather."
Investigation into 2025 outages ongoing
It comes amid an ongoing Ofwat investigation into the water firm after repeated outages between November and January left tens of thousands of households and businesses across Kent and Sussex without drinking water.
Sky News City editor Mark Kleinman also reported last month that a community action group in Tunbridge Wells demanded the "immediate" sacking of South East Water's chief executive after weeks of outages.
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In May last year, Thames Water was fined a record £122.7m for breaches of its rules over sewage discharges and dividend payments.