STAYING in the European Union means "unlimited immigration" into Britain will continue, a veteran Labour MP has said.
Frank Field, who backs Brexit, told voters they will deciding on the UK's "destiny" when they go to the ballot box on June 23.
The outspoken MP for Birkenhead said: "A vote to remain is a vote to take our country firmly and securely into that single state."
Field argued that would represent a "danger" because of the "inevitably of unlimited immigration" from EU member states.
But he claimed a vote to leave could also be "dangerous", saying: "The danger is of a totally unknown proportion".
He added: "Don't be beguiled by the slur tactics of how many jobs we will lose as a result of a vote to leave.
"No honest person knows. The danger is of a totally unknown proportion."
Field, who joined the Commons in 1979, went on to say Brexit has the potential to spark a "freedom flame" across Europe.
Britain quitting the bloc would lead to other nations demanding a referendum on their membership of the EU, he said.
Support for the bloc has plummeted in countries including Germany, the Netherlands and the Czech Republic in the last year.