The campaign to break away from the EU has been boosted after official figures showed net migration levels to the UK climbed to 333,000 in 2015. The Office for National Statistics (ONS) showed the number had jumped by more than 22,000 compared to the same period in 2014.
The research also revealed that 270,000 of the 630,000 people coming to Britain were from the EU, while the net migration levels of EU citizens to the UK hit 184,000, up from 174,000 last year. The data will add further pressure on pro-EU Prime Minister David Cameron, who promised to cut net migration down to "tens of thousands".
Vote Leave and Ukip are also expected to seize on the 333,000 figures – the second highest on record – since immigration is one of the top issues, alongside the economy, in the EU referendum debate.
Steven Woolfe MEP, Ukip's migration spokesman, said: "The sheer scale of immigration is putting our public services under severe strain and causing division and disharmony in our communities.
"We need a migration policy fit for 21st-century Britain which satisfies the needs of our economy and our society. Unless we vote to Leave the EU we will continue to have our hands tied and have no control over who comes and who goes at our ports.
"As a member of the EU, we have a discriminatory immigration policy forced upon us. We let Europeans into Britain in their hundreds of thousands, while imposing heavy restrictions on our friends from Asia, Africa, the Americas and the Commonwealth.
"As it is, our schools and hospitals cannot cope with the ever increasing demand – and our national security is being put at risk as we have no control over who is coming into the country."
Vote Leave campaigner Boris Johnson said: "The public should be able to vote for those who make the laws of this country including on immigration. It is intolerable to continue without democratic consent for Britain's immigration policy.
"That will be best for our public services, particularly the NHS. It will also allow us to have a fairer immigration system that is better for Britain, stops discriminating on the basis of where you come from, and instead allows us to pick people on the basis of skills."
The former Mayor of London added: "Imagine how much stronger we will be, and how much more respected in the world, when we have an immigration policy that stops discriminating on the basis of whether you are an EU citizen and instead selects people on the basis of their contribution to this country.
"The British public support immigration but they want it controlled by those who they elect. They are generous but feel their generosity has been abused."