Yvette Cooper has warned the Labour Party not to lurch to the left or right after its heavy election defeat; instead, it should reach out to the wider British public.
Writing in the Huffington Post, she hit at leadership rivals who believe "there needs to be blood on the floor for the Labour party to rise again".
Cooper is running for the leadership of the Labour party, with her two main rivals being the bookies and the unions favourite Andy Burnham and Blairite Liz Kendall.
In what appeared to be a direct swipe at her rivals, she said "doing what we've done before but shouting that little bit louder" would not work, in an apparent swipe at Burnham; and neither would "swallowing the Tory manifesto", a comment thought to be aimed at Kendell.
In a bid to portray herself as a unifying figure, cooper said Labour "can't fight and win by remaining a narrow party, we have to reach out".
Cooper, the shadow home secretary also criticised colleagues who have claimed that Labour cannot win the next election and urged the party to focus on a "2016 strategy" of winning elections for the Mayor of London, Welsh Assembly and Scottish Parliament.
"I want this debate – about our party, our country – to be as wide and as engaging as possible," Cooper said. "That means as many people as possible involved in the leadership election, not just a closed-down or polarised contest."
A number of other candidates have raised concerns that Labour support for Burnham and Cooper threatens to squeeze them out of the leadership race.
Potential candidates need the support of 34 additional Labour MPs to enter the leadership contest.
The shadow education secretary, Tristram Hunt, decided not to enter the leadership contest after struggling to find the enough backers and has thrown his support behind Kendall's campaign.
Cooper delivered a scathing assessment of the party's "failed" strategy under Miliband in the article.
"Bluntly, not enough people trusted us with their future," Cooper said. "Not enough people were convinced we could do the job."
Her husband, the former shadow chancellor Ed Balls said he was not looking to return to frontline politics after losing his seat at the election, the BBC reported.