Labour leader Sir Keir Starmer has said the party will vote in favour of the Government’s “thin” EU deal, saying that no deal is simply not an option.

The fervent pro-European said it was “in the national interest” to support the agreement despite concerns over the terms negotiated by the Government.

Sir Keir said: “At a moment of such national significance, it is just not credible for Labour to be on the sidelines.

“That is why I can say today that when this deal comes before Parliament, Labour will accept it and vote for it.

“But let me be absolutely clear – and say directly to the Government – up against no deal, we accept this deal, but the consequences of it are yours.”

He said no deal would lead to “devastating” social, economic and political consequences, and said it was not right for Labour to abstain.

Sir Keir denied the suggestion the decision to vote for the deal was in response to appease of large swathes of Brexit-supporting Labour voters at the last general election.

He said: “These are difficult and tough decisions.

I think many people will see this as a tough but necessary decision on behalf of the Labour Party, the Labour movement and on behalf of our country

“But in the end there is only one choice – a binary choice here.

“Either we support the deal or we support the alternative, which is no deal.

“We have always been against no deal and that is why we will vote for this deal.

“I think many people will see this as a tough but necessary decision on behalf of the Labour Party, the Labour movement and on behalf of our country.”

The Labour Mayor of London Sadiq Khan said: “Whichever way you slice it, there is no doubt that this deal falls short of what’s best for London, the UK and our economy. It does not come close to the benefits we enjoyed as members of the EU.

“However, this is the deal now on the table. While we still need to see the detail, we now have a direct choice between this agreement or a catastrophic no-deal Brexit.”

Mr Khan later criticised a “costly, red tape mountain” he said would be imposed from January 1.