16 March 2011
A US government-chartered flight was the first to leave Tokyo's Narita Airport bound for Taiwan.
France and China are also to evacuate thousands of nationals, while the UK and Australia have advised citizens to leave Tokyo.
The Foreign Office said in a statement: "Due to the evolving situation at the Fukushima nuclear facility and potential disruptions to the supply of goods, transport, communications, power and other infrastructure, British nationals currently in Tokyo and to the north of Tokyo should consider leaving the area.
The Statement went on to say, ‘The first option for leaving Japan should remain commercial routes', however the UK government has organised three evacuation flights, with the first due to depart Tokyo at 20:55 Friday 18 March. Two additional flights will operate on Saturday.
The Statement went on to say that the present advice does not apply to Hokkaido, due to its significant distance north of Tokyo.
Qantas is believed to have drawn up evacuation contingency plans should the threat of radiation leaks intensify.
Many multinationals are evacuating staff or moving them further south in the country at reports that Japan has raised the alert level at the Fukushima nuclear plant from four to five on a seven-point international scale for atomic incidents.