The Government has warned against "all but essential" travel via Sharm el-Sheikh airport in Egypt after concluding that intelligence suggested there was a "significant possibility" that a Russian airliner was brought down by a bomb.
Foreign Secretary Philip Hammond said all flights to the popular Red Sea resort had been halted and emergency security boosts were being put in place to ensure British tourists could fly home safely.
The decision follows a review of the airport's security by a team of British experts which reported to a meeting of the Government's emergency Cobra committee chaired by Prime Minister David Cameron.
Egypt's foreign minister attacked the move as a "premature and unwarranted" step which would damage his country's tourism industry.
But Mr Hammond said the safety of Britons came "above all other considerations" and the Government was prepared to take the criticism.