All travellers from the countries involved were already required to get visas to visit Britain but now they will have to be in possession of the documents just to pass through an airport on their way to another destination.

The changes apply from midnight on Monday and apply to Albania, Belarus, Burma, Burundi, Gambia, Ivory Coast, Liberia, Former Yugoslav Republic of Macedonia, Moldova, Nepal, Palestinian Territories, Rwanda, Senegal, Sierra Leone, Sudan and Vietnam.

Home Office minister Beverley Hughes said: "We are determined to take all necessary steps to ensure the integrity of our borders.

"Unacceptably high numbers of people are refused leave to enter the country when they arrive at our airports and some may go on to make unfounded asylum claims.

Grace period

"The ability to travel to the UK without a visa when claiming to be on the way somewhere else is a relatively cheap and easy way to circumvent our immigration controls.

"We are tightening up our procedures to put a stop to this abuse."

People who had already made travel plans on or before 23 June will still be allowed to travel until 28 June.

The grace period will also apply to those on the return leg of a journey begun before Monday.