The process of evacuating Britons from Japan continued in earnest today with buses and planes being used to ferry people to safety.
Some 24 British nationals left tsunami-flattened Sendai at midday local time on two coaches heading for Tokyo.
Once there they will be able to leave the country by plane after the Foreign Office block-booked seats on commercial flights.
The move comes as Japanese authorities raised the severity level at the crippled Fukushima Dai-ichi plant from four to five on the seven-point scale for nuclear accidents.
A Cathay Pacific flight will leave the Japanese capital at around 9pm local time tonight heading for Hong Kong with space for 200 Britons. So far 43 British and other eligible nationals have registered for a seat.
The Foreign Office said two other flights would be made available tomorrow - a Hong Kong Airlines flight and an Orient Thai Airlines plane, both destined for Hong Kong.
Those directly affected by last week's devastating earthquake and tsunami can fly free of charge.
But people wishing to leave Japan who have not been directly affected will pay around £600 per seat.
English teacher Maddie Smith, from Suffolk, was one of those leaving Sendai today.
The 23-year-old, from Burgh St Peter, near Beccles, who has been in Japan since December, told the Norwich Evening News: "We are getting on an embassy bus that goes to Tokyo, then from there we are heading south of the country to keep away from the nuclear plant.
"We did want to stay and help but do not want to take up their limited resources and feel it is not so safe any more with the nuclear problems."
The evacuation gathered pace as the situation at the dangerously overheated nuclear plant continued to deteriorate.
This morning military fire engines were spraying the reactor units with tonnes of water in desperate attempts to douse them and prevent meltdowns that could spew dangerous levels of radiation.
Last week's 9.0-magnitude earthquake and tsunami in the country's north east left more than 6,500 dead and more than 10,300 missing and set off the nuclear problems by knocking out power to cooling systems at the Fukushima Dai-ichi plant.
Since then, four of the plant's six reactor units have seen fires, explosions or partial meltdowns.
The unfolding crises have led to power shortages in Japan, forced factories to close, sent shockwaves through global manufacturing and triggered a plunge in Japanese stock prices.
Meanwhile aid charities said they were encountering "profound humanitarian need" in large swathes of the north east of the country, with thousands of tsunami refugees left homeless and starving as freezing temperatures compound their misery.
Stephen McDonald, Save the Children's response team leader, said: "What we've seen over the past few days has convinced us of the need to expand the work we are doing.
"We've seen children suffering with the cold, and lacking really basic items like food and clean water.
"Tomorrow we're giving out blankets, and our team in Tokyo is looking into what other goods we can supply.
"As we push up the coastline from Sendai, we are finding pockets of profound humanitarian need, and we're going to do everything we can to meet them while remaining focused on our child protection work."
Some 17,000 Britons were believed to be in Japan when the catastrophe occurred last Friday.
The number of British citizens remaining in the country is still not known.
There are no reports of any British casualties following the quake and tsunami.
The raising of the severity level at Fukushima Dai-ichi further ramped up international tensions about the unfolding atomic incident.
The scale defines a Level 4 incident as having local consequences and a Level 5 incident as having wider consequences.
The hallmarks of a Level 5 emergency are severe damage to a reactor core, release of large quantities of radiation with a high probability of "significant" public exposure, or several deaths from radiation.
A partial meltdown at the Three Mile Island nuclear plant in the US in 1979 was also ranked a Level 5.
The Chernobyl accident in the Ukraine in 1986, which killed at least 31 people with radiation sickness, raised long-term cancer rates, and spewed radiation for hundreds of miles, was ranked a Level 7.
France's Nuclear Safety Authority has been saying that the crisis in Japan should be ranked Level 6 on the scale.