Minister says immigration caps not necessary

David Cameron has indicated that a Conservative government would seek to limit net immigration to the "tens of thousands" a year as part of moves to stop the population reaching 70 million and placing a strain on public services.

A YouGov poll of 57 key marginal constituencies carried out for pressure group Migrationwatch found that 44 per cent of voters in Labour-held swing seats would be more likely to back the Conservatives if Mr Cameron pledged to set a 50,000 annual limit on immigration.

But Mr Denham said such a policy could prevent key individuals like international heart surgeons or business leaders from coming to the UK if they were the "first person after the cap".

Insisting that a points-based system was the best way of dealing with immigration, he also said that senior Ministers believed the right controls were already in place.

"We don't think population is going to go to 70 million, so there is a bit of a straw man there," Mr Denham said

"We have got tight immigration control – the points-based system that is now in place means that people can only come here if what they are going to give to this country is something we need."

Mr Cameron has stopped short of stating exactly what level the Conservatives' proposed cap on immigration would be set at, but made clear it would be dramatically lower than present levels.

Net immigration to the UK was just 237,000 in 2007.