Gordon Brown has denied that Britain has experienced unsustainable immigration but defended his "British jobs for British workers" slogan.

However giving evidence to the liaison committee of senior MPs on Thursday, the prime minister insisted that the new point-based system for work permits would make immigration more manageable.

Statistics released this week revealed that up to 80 per cent of jobs created in Britain over the last decade might have gone to foreign workers.

But pressed as to whether this was an "unsustainable" rate, putting pressure on public services, Brown said: "I'm not going to say that."

"We now know that there are far more people in the rest of the world looking to come to the UK," he said.

However he said the point-based system would allow employers to recruit workers whose skills are needed in the economy.

Net migration

Asked whether the points system was intended to reduce net migration, Brown said it was not.

"The points system is to give us a choice as to the people we are letting in to Britain to work," he said.

"We as a country must set the rules that we think are appropriate for the future," the prime minister added, "bearing in mind" Britain's obligation as a member of the European Union, to spouses and dependents if migrants, but also increased global migration.

He rejected Conservative plans for an annual limit on net migration, as a "cap would include skilled workers" needed by firms in the City of London, for example.

In contrast he said the points system would filter out the "unskilled" people coming to the country who "we don't need".

British jobs

Brown was also challenged over his pledge to provide "British jobs for British workers" in recent speeches, seen by some as unworkable and potentially inflammatory.

He pointed out that there are fewer foreign-born workers in jobs in Britain as a proportion of the population than in Australia, Canada or America.

However he added that there are also 600,000 job vacancies in the economy, while five to six million jobs change hands every year

And Brown said his slogan referred to the need to ensure that people either unemployed or economically inactive have the skills necessary to take the posts up.

"My responsibility is to do everything in our power to make sure that these people are available to take the jobs," he said.

"The issue is not a lack a jobs. The issue is a lack of skills for jobs."