Mr Darling, who led the campaign for Scotland to remain in the UK, said: “I have known Ian since he was a Labour councillor in Edinburgh, and he has always been a champion for his city and his country.

Tony Blair and Gordon Brown publicly endorse the direction Ian Murray wants for ...

“The Labour Party needs to change to return to power and defeat SNP and Tory nationalism, so that we can grow the economy, create jobs, lift people out of poverty and give everybody a fair chance in life once again.

Alistair Darling has endorsed Ian Murray. Picture: JPI Media / BBC

“Ian is the deputy leadership candidate best placed to demonstrate that Labour is a party for the entire UK, and he will deliver the change our party and our country needs.”

'Perpetual opposition'

Mr Ian Murray said: "When Labour is in government, we have chancellors like Alistair who build economies that work for everyone.

“But when we are in opposition we are at the mercy of Tory chancellors who inflict cuts on the most vulnerable in society.

“Without change, we risk becoming a party of perpetual opposition. We need to become a credible alternative government so that we can return to power and build a fairer economy once again.

“That is why I am standing to be deputy leader, and I’m delighted to have Alistair’s support.”

Elected in 2010, Murray held on to his seat for Labour after the retirement of the incumbent, when his party was going backwards and Edinburgh South was the number one Liberal Democrat target.

He was one of the earliest movers on the Labour benches pushing the party to back a second referendum on EU membership. And he’s survived two historic SNP landslides that have left him the sole Labour MP in Scotland.

Alistair Darling backs Ian Murray for deputy Labour leadership