Labour has never elected a female leader - Margaret Beckett and Harriet Harman have both stepped up temporarily from the deputy role - and Ms Cooper has long been tipped to be the first.
The Shadow Home Secretary, who represents Pontefract and Castleford, has built a reputation as a safe pair of hands in a succession of ministerial and opposition jobs, rarely if ever finding herself embroiled in controversy.
However she might struggle to broaden Labour’s appeal and the party is likely to think twice about electing a politician who will be immediately portrayed by the media as ‘Mrs Ed Balls’ - a reference to her husband after the Shadow Chancellor lost his Morley and Outwood seat.
Consistently tipped as the dark horse in the potential field of replacements for Ed Miliband, the Barnsley Central MP certainly appeals to those seeking a move away from career politicians.
In 2011 he ended a 15-year career as a Para, including tours in Afghanistan, Iraq and Kosovo and as a special forces support group company commander, for a safe seat in the Commons - the first to make such a switch since the Second World War.
The married father-of-three was quickly handed shadow ministerial roles in culture and justice. He swerved the question of whether he would throw his hat in the ring after increasing his majority in Barnsley Central in the General Election, but he does have the ability to lead Labour from the political centre and is not hamstrung by the party’s past record.
The veteran ex-cabinet minister’s name will inevitably crop up in speculation about the possible line-up of candidates despite insisting recently that he had never stood for the leadership of his party and “regardless of the circumstances never will”.
His stature in the party was in evidence last year when he was said to have been approached by senior figures in the party to consider taking on the role amid a bout of internal wobbles over Mr Miliband’s performance.
A former postman and senior union official whose memoir of a poverty-ravaged childhood in London slums proved an instant hit, he was Mr Miliband’s first choice as shadow chancellor before quitting for personal reasons.
However the West Hull MP might be a potential interim leader if Labour hold a prolonged contest to pick Mr Miliband’s successor.
Fourth out of the five in the last leadership contest in 2010, the 45-year-old MP for Leigh is the bookies’ favourite to win the next one and has strong support among trade unions who will hold the balance of power.
Holding the key health brief in government and opposition for most of the last six years has helped make the 45-year-old a darling of the Labour grassroots. However critics fear he would be vulnerable to attack because of being health secretary at the time of the Mid Staffs excess deaths scandal.
His entire political modus operandi has been based on scare-mongering over the NHS and his election would represent a continuation of the flawed approach pursued by Mr Miliband – both men have repeatedly refused to apologises for the spending excesses of the past Labour government.
A rapid rise to the shadow cabinet makes it easy to forget the he has only been an MP since 2010 so could certainly be presented as a fresh face.
The sharp-suited, smooth-talking former employment lawyer has made a mark as shadow business secretary and has previously declined to rule out a leadership bid.
In 2011 the sometime DJ who ridicules the “British Obama” epithet attached to him as the man most likely to become Britain’s first ethnic minority party leader.
A confident media performer, some Labour analysts believe Mr Umunna is guilty of over-estimating his own self-importance.