South Africans need visas for UK

The changes will also apply to people from Bolivia, Venezuela, Swaziland and Lesotho. Citizens of those countries will be required to provide their fingerprints before they travel.

Ministers changed the rules following a review of countries exempt from visa regulations because of fears of lax passport checks.

There were concerns that people from countries neighbouring South Africa were obtaining travel documents and coming to Britain without stringent security checks.

Fears were raised that al Qaida could be using the route as a way of getting terrorists into Britain.

Home Secretary Jacqui Smith told MPs: "We are introducing new visa requirements for Bolivia, Lesotho, South Africa, Swaziland and Venezuela. Visitors from these countries will need a six-month visa and they will need to provide their fingerprints before travelling here.

"Those travelling via the UK will also need a transit visa. These new requirements are in addition to the existing requirements for a visa to live, work, study and marry in the UK.

"They form part of the biggest-ever changes to strengthen Britain's border security through stronger overseas checks, tougher border checks and robust enforcement action within the UK."

First-time visitors will be affected from the beginning of next month, and the rules will be fully enforced by the middle of this year.

The move will affect more than 420,000 South Africans who come to Britain every year, and 30,000 Venezuelans.