Labour leadership candidate Ed Miliband says he wants to win back the voters that Tony Blair attracted in 1997.
The former energy secretary, younger brother of former foreign secretary David Miliband, said he would be able to "unite the party" as Labour leader.
And he said deciding to run against David was one of the "hardest decisions I've made in my life".
The two Milibands are the first figures to formally throw their hat into the ring for the party leadership.
Ed Miliband told BBC1's Andrew Marr Show that he wanted Labour to "reconnect with the people we lost".
He said: "We lost different groups in the population. We lost people who have been traditionally Labour voters over issues such as immigration.
"I think we also lost the voters that Tony Blair attracted to our party in 1997 and I would want to win them back and I would make that a very important part of my leadership."
He added: "I would try and bring my sense of idealism and values, my sense of empathy and my ability to reach out and understand people's lives and my ability to unite the party."
But two newspaper polls today suggested that David Miliband enjoyed the backing of almost a third of voters.
An ICM poll for the Sunday Telegraph put the South Shields MP on 32%, Harriet Harman on 11%, Ed Miliband on 9%, Ed Balls on 8% and Andy Burnham and Jon Cruddas on 2% each.
