Labour MP Tom Blenkinsop has announced he will not run for re-election after Theresa May announced a snap general election.
The MP for Middlesbrough South and East Cleveland, who was first elected in 2010, announced he would step down because he could not "in good faith" fight a general election campaign while Jeremy Corbyn is leader.
In a statement delivered outside 10 Downing Street Ms May announced the snap election on 8 June, saying she wanted to "remove the risk of uncertainty and instability and continue to give the country the strong and stable leadership it demands".
But critics will point out several polls, including one by The Independent, released over the weekend which showed the Conservatives are currently enjoying a 20-point lead over Jeremy Corbyn's Labour party would have almost certainly factored into her decision.
Mr Blekinsop regained his seat in the 2015 election with a majority of 2,268 but is an outspoken critic of Mr Corbyn's leadership, having supported Owen Smith during the bid to oust him last year.
In a statement on his website, he said: “I will not seeking re-election as the member of Parliament for Middlesbrough South and East Cleveland.
“I have made no secret about my significant and irreconcilable differences with the current Labour leadership. It is because of these differences I feel I cannot in good faith stand as the Labour candidate for Middlesbrough South and East Cleveland.
“Representing the people of Middlesbrough South and East Cleveland has been the proudest years of my life.I will do all I can in my time remaining as an MP to champion my constituents and the area that means so much to me, as I have been proud to do over the last 7 years.”
He blamed the Labour leader for the party's lost of a safe council seat in his constituency to the Conservatives earlier this month.
He said: "We lost due to the leader's name being mentioned on the doorstep as the reason why residents were not voting Labour."
Middlesbrough, in North Yorkshire, is considered part of the traditional Labour heartland but voted for Brexit in the referendum last year.
Mr Corbyn is facing a possible wipeout with some speculating he could lose up to 100 seats in this new general election.
Despite this, he "welcomed" Ms May's announcement.
He said: "I welcome the Prime Minister’s decision to give the British people the chance to vote for a government that will put the interests of the majority first," Mr Corbyn said in a statement.
"Labour will be offering the country an effective alternative to a government that has failed to rebuild the economy, delivered falling living standards and damaging cuts to our schools and NHS.
"In the last couple of weeks, Labour has set out policies that offer a clear and credible choice for the country. We look forward to showing how Labour will stand up for the people of Britain".
