LONDON The Conservatives pledged to cap immigration on Tuesday and were warned by a business organisation this could cut productivity and damage London's global competitiveness. Launching their election manifesto, the Conservatives, who have claimed the backing of several prominent business leaders during the campaign, promised to impose an annual limit on the numbers of non-EU economic migrants allowed to work in Britain.
"Britain can benefit from immigration, but not uncontrolled immigration," the party said, citing the impact of a rising population on public services and local communities.
"A Conservative government will reduce immigration to the levels of the 1990s - tens of thousands a year, instead of the hundreds of thousands a year under Labour."
Jo Valentine, chief executive of business group London First, said encouraging talented professionals to base themselves in London, through tax and immigration policies, was vital to Britain's economy and ensuring future growth.
Valentine said her warning was not aimed solely at the Conservatives who are leading in opinion polls ahead of the May 6 election.
"All three main parties have privately shared sensible views on the value which these globally mobile, talented individuals bring. My worry is that these will be overlooked in the search for votes," she said.
"Artificial caps could damage London's competitiveness and ultimately its standing and success as possibly the most cosmopolitan city in the world."
Voters cite immigration as the second most important issue after the economy. The anti-immigration British National Party won two seats in the European Parliament last year.
It is not expected to win any seats in the election but could pick up votes from both main parties and influence the outcome in the fight for marginal seats in the 650-member parliament.
Net immigration by non-British citizens increased from 89,000 in 1991 to 251,000 in 2008, according to data from the Office for National Statistics.
It hit a peak of 352,000 in 2004 but in recent years it has declined after European workers returned home. Britain has a population of more than 61 million.
(Reporting by Kylie MacLellan; editing by Robert Woodward)