Wakefield MP Mary Creagh has vowed to “earn back the trust of voters” as she announced she will stand to be the leader of the Labour party.
Ms Creagh joins Normanton, Pontefract and Castleford MP Yvette Cooper in the battle to replace former leader Ed Miliband who announced his resignation following last week’s general election result.
Labour lost 56 seats in Scotland to the Scottish National Party and won almost 100 fewer seats across the UK than the Conservatives.
Ms Creagh and Ms Cooper join Andy Burnham and Liz Kendall in the race after Streatham MP Chuka Umunna withdrew from the running on Friday morning.
Ms Creagh said: “I think we need to earn back the trust of voters and build a coalition that can represent working people right across the country.
“The election was a terrible disappointment. It was a crushing defeat for the Labour party and I am very sorry for the nine-million people who voted for us that we weren’t able to overcome the Tories negative campaigning.
“They played very much on fears around Scotland and ran a very negative campaign about what might happen.”
Ms Creagh said she thought Labour’s defeat was because voters “didn’t trust the party with the economy.”
She said: “I think we, as a party, have got a lot of soul searching to do. We campaigned a lot on the NHS, which people have a lot of passion for, but is not normally a reason why people vote.
“I just feel people need a Labour Prime Minister who is courageous.”
The former shadow health minister, who increased her majority to 2,613 in last week’s election, reassured her Wakefield constituents that she would not let her leadership campaign stop her from representing their issues.
She said: “I have a phenomenal appetite for hard work and I think it’s very important for me to be in Wakefield and talk to people.
“That’s also part of the process of finding out why we lost the election.”
On Thursday Ms Cooper also announced she would be standing for leader. The Normanton, Pontefract and Castleford MP said she wants to be a “strong leader who represents Labour values.”
But Ms Creagh said she had not spoken to her before announcing her own plan to replace Mr Miliband.
Ms Creagh said: “I wish Yvette well. She is a brilliant colleague and friend and she is a very strong person. I haven’t spoke to her about my announcement but I think there must certainly be something in the Yorkshire water.
“My focus now is on speaking to my colleagues and getting the nominations I need so that I can restore the trust we have lost.”
Ms Cooper is now the bookies’ second favourite behind Andy Burnham, with Mary Creagh ranked fourth.
Ms Cooper said: “We, as a party, have got to work harder and have to do more to show how much help we can give hard-working people who are ambitious for the future - and I intend to do just that.”
Under the timetable set out by Labour’s national executive, nominations for leader will close on June 15 and for deputy leader at noon on June 17.
The result will be announced on September 12.