Former Energy and Climate Change Secretary Ed Miliband joined his elder brother in the race for leadership of Britain's Labour party on Saturday, saying the centre-left party had lost touch with its progressive values.
On Wednesday former Foreign Secretary David Miliband was the first senior party figure to announce his bid for the leadership, a day after Gordon Brown resigned as prime minister and leader of the centre-left party.
"I have decided to stand to be leader of the Labour party," Ed Miliband, 40, said in a speech to the Fabian Society, a centre-left think tank.
"We lost touch with the values that made us a progressive force in politics and we lost touch with the people we sought to represent."
The Labour leadership race is likely to turn into a battle between left and right wings of the party, both of which will draw different lessons from its defeat in last week's election.
David Miliband, regarded as a "Blairite", is the favourite of the right of the party. The brothers are likely to face a challenge from a more left-leaning candidate such as former Schools Secretary Ed Balls.
While Ed Miliband is less well known to the public than his brother, he is popular within the party and has the support of the trade unions, Labour's biggest financial backers, giving him support from both left and right.
The party, which grew out of the trade union movement and was founded in 1900, swung to the left in the 1980s and lost a string of elections before Tony Blair moved it to the centre. He was prime minister for a decade from 1997 before handing over to Brown.
In a speech that was highly critical of his party's 13 years in government, Miliband said that while Labour had done much to be proud of in the early years, it had been left behind on many issues, including the economy, fairness and immigration.
"My message to the British people is we will learn from our mistakes, we will be part of your values again, we will be part of your community again and we will work with you to build the kind of country we want to see," he said.