Britain's first government-chartered repatriation flight from the Middle East reportedly never left the ground on Wednesday night, stranding families on a bus beneath the aircraft in scenes one passenger described as a "total s---show."

The flight out of Muscat had been billed as the Foreign Office's opening move in getting British nationals home — its sole organised evacuation in the five days since fighting erupted across the region. It was due to lift off at 11pm local time, 7pm in the UK.

Instead, according to Sky News, a cascade of technical and administrative failures brought the boarding process to a standstill. Passengers — among them families travelling with young children — found themselves marooned on a bus on the tarmac as the situation deteriorated around them. Some grew agitated. Others hammered on the windows. A number suffered panic attacks.

One passenger told TV crew the unfolding chaos was "incredibly serious" and that consular officials on the ground had been conspicuous by their absence.

The final blow came when the pilot was pulled from duty after exhausting his legally permitted flying hours. The entire group was ferried back to their hotel. A fresh departure is expected sometime on Thursday.

The Foreign Office has been contacted for comment.

The debacle on the ground in Muscat unfolded as Israeli forces unleashed another round of strikes on Iran on Thursday morning, sending massive explosions reverberating across Tehran. Iran fired back with missiles aimed at Jerusalem and Tel Aviv.

The numbers of Britons waiting to get home remain enormous. Some 130,000 British nationals have logged their whereabouts with the Foreign Office, which is in talks with airlines about unlocking more routes out of the region.

Wednesday's aborted Muscat departure remains the only government-organised flight attempted since the conflict began. A small number of commercial services out of Dubai and Abu Dhabi made it back to Britain on Monday and Tuesday, but the overwhelming majority of stranded nationals are still waiting.

Yvette Cooper signalled to MPs on Tuesday that getting British nationals home was a "top priority" for the Foreign Office, having earlier pointed to Oman as the most viable jumping-off point for any evacuation effort.

For those stranded in Dubai — the emirate where most British tourists and expats are concentrated — Muscat represents a 280-mile road journey before they can even board a flight.

Travellers caught up in the crisis are being advised to keep a close eye on communications from their airline or tour operator and to scrutinise their travel insurance cover before attempting to leave.