Labour at its 1990 conference set itself the target of splitting Commons representation 50-50 between men and women MPs by 2000.
But with only 36 women in the 270-strong Parliamentary Labour Party and only 20 to 30 Labour seats becoming vacant through retirement or by-elections, there are strong demands for further constitutional changes.
Clare Short, who chairs the Labour national executive's women's committee, said last night that the executive had asked a sub-committee to propose a mechanism for increasing the number of women parliamentary candidates, to be considered by this year's party conference.
The conference is certain to step up the pace of change - the only question is over the process to be used.
Ms Short said: 'I very much hope that the sub-committee will recommend a mechanism that requires all-women short- lists in half of the selections in each region for each of three categories of seat - the safe, the marginal and the unwinnable.
'That would deliver a parliamentary party that's half women in a little longer than the target year 2000. But it will deliver.
'If that doesn't happen, then I think there will be demands for a more rigid formula that would say every single retiring Labour MP and every winnable by-election should be contested by a woman, which would be very hard on good men because it would wipe out a generation of male politicians until we reach the 50 per cent target.'
The Labour women's conference in Llandudno decided this month that all-women shortlists for the selection of candidates for by-elections and the replacement of retiring MPs was 'the very minimum that can be undertaken by the party to achieve its policy'.
One party worker said yesterday that the sacrifice of one male generation, suggested by that mechanism, had to be balanced against the generations of women that had already been lost to the party.
But the demand for dramatic action has also been fuelled by the realisation that, under its current, voluntary system, Labour is about the lose one of its seven-strong contingent of women Members of the European Parliament - something described as a 'disastrous step backwards' by one woman Labour MP this week.
The Labour selectorate in the Euro-seat of Glasgow has already chosen a man to replace Janey Buchan, the retiring MEP; Glenys Kinnock is trailing John P Smith, former MP for Vale of Glamorgan, in nominations for the Labour-held seat of South East Wales; and the only other woman contender is Rosie Winterton, former assistant to John Prescott, Labour's transport spokesman.
She is challenging Richard Balfe, the sitting MEP for London Inner South.
Certainly, women are not the only radicals on the issue. Max Madden, who at the weekend announced his intention of retiring as Labour MP for Bradford West at the next general election, said yesterday: 'We have got to bite the bullet.'