Tony Blair has admitted he did not realise how many migrants would come to the UK when he opened Britain’s borders to millions of European workers.

The former Labour leader relaxed immigration controls in 2004 after 10 new nations including Poland, Lithuania and Hungary, were admitted to the EU.

He tried to play down the significance of opening Britain’s borders, arguing that most EU migrants came to the UK after 2008.

However, official figures show that the number of EU migrants who came to Britain rose from just 15,000 in 2003 to 87,000 the following year. That figure increased to 104,000 in 2006 and 127,000 in 2007.