Many countries are tightening their immigration laws, shifting to a skills-based immigration system and setting citizenship tests for would-be immigrants.

ECONOMIST: Europe and Islam

Many parts of the immigration system are still based on quotas.

WSJ: Crovitz: The Economics of Immigration

Sir Andrew also said the government's points-based system to control non-EU immigration had so far "had very little effect".

BBC: Crowds of people

"We have made it clear that the points based system will allow the Government to manage immigration which in turn will help contribute to future population projections and control, " said the spokesman.

BBC: Citizenship test plans published

He also said he had been given the position of immigration minister "to change perceptions" and raise the profile of the new points-based system - which he said was "tougher" and the biggest shake-up of immigration policy in 45 years.

BBC: Woolas defends population pledge