"I don't think that the public see the UK Labour Party led by Jeremy Corbyn at the moment as being a credible party of future government in 2020," Mr Murray, Labour's only MP in Scotland, told BBC Radio 4's the World at One.

"That's something, after this week's results, we should reflect on, the leadership of the party should reflect on - and find a way of finding a strategy and a narrative that changes the perception of the UK Labour Party across the United Kingdom so that we can go on and have a real shot at winning in 2020."

Corbyn refuses to quit

Addressing supporters in Sheffield after a dismal night for Labour, Mr Corbyn has admitted the party has "a lot of building to do" in Scotland but brushed aside suggestions that he should stand down.

He told the Press Association: "I'm carrying on. Don't worry about that. I'm carrying on. I'm fine. I'm very happy."

Shadow chancellor John McDonnell said it was time for Mr Corbyn's critics in the party to "Put up or shut up".