John McDonnell said he felt there was no other option that could offer the same benefits as staying in the EU

John McDonnell has declared that he would campaign to stay in the EU against a Brexit deal negotiated by Labour, piling more pressure on Jeremy Corbyn to support remaining in the bloc in all circumstances.

The shadow chancellor said that a Labour government would put Brexit back to the people in a second referendum but that regardless of what might be the other option on the ballot paper he would back Remain.

Labour’s present policy, if Mr Corbyn becomes prime minister before the UK has left the EU, is to hold a referendum between staying in the EU and a Leave option.

Mr McDonnell told Today on BBC Radio 4: “I think generally people want to provide the electorate with a choice. I’ve made it