Cameron pledges to cut immigration

In his first major speech on immigration, Mr Cameron set out his "modern Conservative population strategy" to slow the rate of growth in the numbers of people living in the UK.

A Tory administration would set annual limits on economic migration from outside the EU "substantially lower" than the current rate, set up a Border Police Force with powers to track down and remove illegal migrants, and impose transitional controls on the right of nationals of new EU states to work in the UK.

And Mr Cameron said he would raise the minimum age for spouses coming to Britain to 21 and demand that they are able to speak English. A failure to reduce net immigration would "make it more difficult for a Conservative government to deliver its vision of opportunity, responsibility and security", he warned.

The Conservative leader also cautioned: "The promises that Gordon Brown makes - whether on improving the NHS, the education system or housing provision - will quite simply be overwhelmed by his failure to deal with the root causes of our demographic challenge."

Latest figures from the Office for National Statistics suggest, on current trends, the UK's population will rise from 60.6 million to more than 71 million by 2031, increasing pressure on housing, healthcare, schools, the transport system, energy and water supplies.

Some of the increased pressure comes from Britain's ageing population, as well as the "atomisation" of society through divorce, family break-up and later marriage, which means more single-person households, said Mr Cameron. But with 190,000 more people coming to the UK from abroad than leave the country each year, the bulk of the population rise - around 70% - is driven by immigration.

"Of course we should recognise that in an advanced, open economy there will be high levels of both emigration and immigration," said Mr Cameron in his speech in central London.

"But what matters is the net figure, which I believe is currently too high... It is time for change. We need policy to reduce the level of net immigration. And we need policy to strengthen society and combat atomisation."

Immigration minister Liam Byrne accused Mr Cameron of "rehashing platitudes". "He talks of a limit on immigration numbers but nowhere does he say what this would be," he said.