The shadow secretary of state for Scotland, Dave Anderson, will stand down after the election in June, forcing Jeremy Corbyn to find a replacement.
Mr Anderson, the MP for Blaydon in the northeast, announced he will not seek re-election.
He was appointed to the shadow Scotland and Northern Ireland portfolios after the mass resignation of Mr Corbyn’s front bench, including Ian Murray, Labour’s only MP in Scotland.
Mr Anderson, 63, had previously attacked the Barnett Formula that provides funding to the Scottish Government, and last year said that he would be “delighted to pass this job on to someone else” who could “give it the attention that it fully deserves”.
Despite several reshuffles since his appointment, however, Mr Corbyn has been unable to find an MP to take on the Scotland role full-time.
The former miner and social worker said health issues were behind his decision.
Mr Anderson said: “The calling of this election is nothing more than a cynical attempt by the Tories to put their interests before our country.
“However, the decision has been made and I welcome the chance to take Labour’s case out to the people of Blaydon.
“We’ll show them that there is a different, more positive and hopeful way to run our country than that proposed by the right-wing, anti-public service and pro-austerity Tory Party.
“I have reluctantly decided that for reasons of health, age and my family’s needs, I cannot commit to another five years in Parliament.
“To that end I will stand down, but I will be campaigning hard with our new candidate and the positive policy platform put forward by our Leader, Jeremy Corbyn, and the whole Labour movement.”