"I was mightily surprised by his speech. Every key vote that we've had on Europe since I've been in House of Commons and since Jeremy joined the House of Commons, we've actually been in the same lobby together, critical of Europe."

Asked why so many unions, which represent four million workers, had come out in favour of the EU, Mr Field said that they were being represented by "elite" union bosses who "are not representative of the grassroots".

He said he also hoped "good old Labour voters" would vote for Leave and give the government a "friendly punch in the nose."

Highlights from Frank Field's speech