MP Barry Sheerman will be backing Owen Smith for the Labour leadership, it was announced on Wednesday.
The veteran MP pledged his support, saying he has had “misgivings” about Jeremy Corbyn since he was elected.
In an open letter on his website, Mr Sheerman said: “Over the years I have come to know Jeremy Corbyn well but he has never shared my views on loyalty to the party and he has a reputation for having a very different attitude to party solidarity.
“As soon as Jeremy Corbyn was elected leader, although I had misgivings I decided and informed you that I would give him a fair chance.
“Unfortunately Jeremy has been unsuccessful in this regard and the party is struggling to convince potential voters of his ability to lead our country.”
The MP added that Mr Corbyn had “failed abysmally” to lead Labour’s Remain campaign to say in the EU.
In his letter he added: “Having seen Jeremy operate at close quarters I am convinced he does not have the ability to lead the party, indeed I fear an electoral disaster at the next election.
“Locally I think we could be in danger of losing all three Labour seats in Kirklees, as well as dozens up and down the country.
“I will be voting for Owen Smith and I hope you will be able to join me.”
Voting for the next Labour leader will conclude on September 21 with the victor announced at the party’s leadership conference on September 24.