When Margaret Beckett walked into the House of Commons on Tuesday for Prime Minister's questions, she was greeted with the same roar of cheers and boos that used to mark the entry of John Smith. The racket is one of those parliamentary practices, culturally situated somewhere between the debating chamber and the locker room, the roar of the tribe in tribute to its leader. It is only worth mentioning because, as one Labour MP remarked this week, the Labour Party is currently led, for the first time in its history, by a woman.

That, in turn, is only worth mentioning because in the forest of comment, reporting and speculation on the forthcoming leadership contest that has filled the pages of the national press since the death of John Smith, the name of Margaret Beckett has hardly been mentioned. Not only has her name been missing from the discussion of the succession to Smith, it has largely been absent from the discussion of the full ticket. Last week it appeared that Mrs Beckett had been written off from the job she might or might not aspire to hold permanently, and from the job to which she was elected two years ago - that of deputy leader. Mrs Beckett, in a remarkable piece of prestidigitation, has become invisible.

Margaret Beckett is leader of the Labour Party, of course, by default rather than design and it is true, historically, that no deputy leader has yet has managed the transition to leader. In that sense it is an even less rewarding job than that of US vice-president. But she will steer the party for the next several weeks, through Prime Minister's questions, through the European elections, through the internal debate that will accompany the search for John Smith's successor, chairing the committees, fronting the team.

And, despite this uninvited opportunity in her career, her name is absent from the lists at a time when, at every level in the Labour Party bar the top, consideration of women candidates is mandatory and election of women to 40 per cent of party posts is written into the rules. 'When the chips are down,' said one prominent woman backbencher this week, lamenting the phenomenon, 'this is still a boys' party. Leaders wear suits.'

That is one explanation, but not the only one. In the shock that followed John Smith's death, the party imposed a dignified ban on leadership campaigning until after tomorrow's funeral. This self-imposed silence has been honoured by the principal candidates, including Mrs Beckett, but not entirely by their supporters. Tony Blair, John Prescott, Gordon Brown and Robin Cook have their camps, fluid though they may be until the lines of the contest are clear. Margaret Beckett has no camp, so her name is not circulated. But some MPs think it too early to write her off. 'Wait and see what happens once she has been acting leader for a while,' said one Labour MP, 'and people will have been forced to take notice of her. The boys haven't even begun to think what effect that might have.'

Mrs Beckett herself is waiting. But she is in a strong position to bargain. She could decide to run for leader, but would risk the loss of both positions; she could retain her position as deputy leader, at least until the party conference in October and by so doing rule out the so-called 'dream ticket' of Tony Blair and John Prescott; or she could stand down as deputy leader and parley her present position into a firm promise of a senior cabinet post. Which choice she should make depends on several factors, but the fundamental question remains: is she good enough to make it to the top or is she is already lucky to be where she is?

There is no shortage of opinion in the Labour Party, where Mrs Beckett is less than personally popular, that she is lucky to have risen so far. Some politicians contrive to have their better moments remembered. With Margaret Beckett, it is the opposite. Until she rose to make her tribute to John Smith last week in the House of Commons, a performance that won her universal sympathy and praise, the moment best remembered in Margaret Beckett's career was her savage attack on Neil Kinnock at a Tribune meeting in 1981.

That moment, when Tony Benn contested the deputy leadership against Denis Healey, was a critical one for the party. Neil Kinnock abstained in the vote and his abstention, with others, allowed Healey to win. At the Tribune meeting, Kinnock sat, white faced, as Beckett accused him, without naming him, of treason. Her attack enraged a fellow left-winger, Joan Lestor, who had resigned a junior ministerial post in the last Labour government in protest against public expenditure cuts. Margaret Beckett had taken the job. 'I will not take any lessons in loyalty from Margaret Beckett,' she said.

The charge against Mrs Beckett is less that she has moved from far left to centre right: that, after all, is the recent history of the Labour Party. It is more that her shifts are perceived to have been motivated as much by opportunism as by principle. They have lost her friends on the left and failed to win allies on the right: she is vulnerable, as one observer remarked, to the question that haunted Kinnock: what does she really believe in?

Had she been blessed with dazzling gifts of oratory or great personal charm, she might have overcome the handicap of her record. But, though Beckett earns praise for competence, she is not, most agree, an easy character. Her early life offers some sound reasons for her prickly character.

Margaret was the youngest of three daughters of Cyril Jackson, a carpenter from Lancashire, and Winifred, a schoolteacher. Her father became a chronic invalid when Margaret was three and died when she was 12, Her mother, she has said, fell apart. The family's difficulties left her with an abiding anger that little was done to support, or comprehend, those who suffer such misfortunes. The anger translated directly into her party affiliation. Her loyalty is beyond question, but Mrs Beckett is not the sort of Labour Party member who finds much merit in those who are less faithful. 'If you are not in the Labour Party,' said one acquaintance, 'she thinks your opinion is not worth having.'

That may be her core conviction, but, as shadow chief secretary to the Treasury, Mrs Beckett did more than her share of talking to the enemy: she was John Smith's companion on the prawn-cocktail offensive that preceded the 1992 election, helping to convince City gents that Labour could be trusted with the economy. That was the furthest end of the Beckett pendulum's swing to the right. From there, she jumped to deputy on John Smith's leadership ticket, part of a deal with those unions that wanted a woman and a union-sponsored MP for deputy.

All of which could add up to a convincing case for dismissing Margaret Beckett as a potential leader. But this is a sensitive time for a party that has accidentally found itself led by a woman to brush her aside in too cavalier a fashion. Under new voting rules, rank and file party members will have a larger say than ever before in the selection. Even in the Commons boys' club there is some unease lest she be seen to be dismissed too lightly. 'I would vote for her if she stood,' said one left-wing MP this week. 'I don't buy the idea that she is not voter-friendly and I don't like the approach that says the leadership is serious politics, so let's forget Margaret.'

There was cautious agreement from a prominent woman MP. 'It's early days,' she said. 'Nobody is thinking very clearly about what to do. The press, unpolluted by a response from us, has been pushing Blair so hard that nothing else is getting much of a look-in. But after Friday and after the Euro-elections other things will be back on the agenda. One of them will be gender.'

(Photograph omitted)