The UK Independence Party promised to put an annual cap of 100,000 on immigration and withdraw from the Geneva Convention on Refugees if it won power.
The party’s most prominent politician, former TV presenter Robert Kilroy-Silk, announced the new policies with a warning that Britain will need a new city the size of Birmingham every 10 years to house migrants unless numbers are curbed.
Mr Kilroy-Silk accused the Government of lying about the true extent of migration to Britain.
He dismissed Conservative leader Michael Howard as a “political coward” who could not deliver what his party’s natural supporters want on immigration and Europe.
Mr Kilroy-Silk, who won a European parliament seat for UKIP, claimed that schools in some parts of Britain were being “overwhelmed” by immigrants who could not speak English, while health and social services were put under strain by incomers.
He rejected accusations of racism.
“We are not racist,” he told UKIP’s annual London dinner. “We vehemently and vigorously reject all racist language and action.
“We will not tolerate any discrimination on the grounds of race or colour or creed, or indeed age or sex. We will be outspoken in condemning racism wherever and whenever it occurs.”
Mr Kilroy-Silk said that the 100,000 figure would cover all those coming to settle in the UK, including migrants from the European Union, who have an automatic right to live in Britain.
The figure is roughly the same as the number of people leaving the UK each year, allowing the country’s population to be held steady over time.
Immigrants would be admitted on the basis of an Australian-style system of points awarded on the grounds of skills, value to the community and contribution to the national economy, he said.