Britain will begin capping the number of non-European Union migrants coming into the country to live and work for the first time next month, according to Home Office sources. Only 24,100 workers will be allowed in between next month and April 2011 – a five per cent cut on the number who arrived in the same period last year.

The aim is to prevent a sudden influx in arrivals before a permanent annual limit, a key election pledge of Prime Minister David Cameron’s Conservative party, is introduced next year. “It’s not about cutting, it’s about preventing a rush,” a Home Office source said.

Home Secretary Theresa May will announce the measure next week along with a consultation on the annual limit, which was part of the coalition deal agreed between the Conservatives and the Liberal Democrats after May elections.

There will be no restrictions on the number of migrants allowed to come in from an overseas company to a branch in Britain under the temporary cap, while other specific groups – such as elite sports people – will be exempt.

In 2008, net migration to Britain was 163,000. This was down from 233,000 in 2007 but the Conservatives vowed in their manifesto to cut this to levels seen in the 1990s when it was “tens of thousands a year, not hundreds of thousands”. This figure includes EU migrants, over whom the government has no control because of the bloc’s open borders.