Speaking after an AEEU delegation meeting, Ken Jackson, acting general secretary, said his union did not want minority parties dictating policy to the Government - one of the principal objections to proportional representation.
A conference vote on Thursday over whether to reaffirm John Smith's pledge to let the voters decide on the voting system for general elections was already set to be close, and likely to be clinched by the attitude of constituency party delegates who have 30 per cent of the conference vote.
Among the large unions accounting for the lion's share of the 70 per cent block vote, the GMB is ready to reaffirm its backing for a referendum, although it still favours first-past-the-post itself. But if the AEEU joins the TGWU and possibly Unison, the vote could be lost.
Jack Straw, the shadow Home Secretary, personally backs keeping first- past-the-post but will make a strong appeal in his speech on Thursday for Mr Smith's pledge to be retained, arguing that 20 years of argument must be resolved by asking the British people. And the party's national executive committee yesterday decided to support a motion favouring a referendum, instead of remaining neutral as in the last two years.
One key campaigner for the reform said yesterday: "It would be a democratic outrage if this is determined by the union block vote."
But speaking at a fringe meeting, the left-wing Alice Mahon, MP for Halifax, said "certain people" on the NEC had changed their minds because they were "running scared and would welcome perpetual coalition with smaller parties. I think the moves to snuggle up to the Lib Dems are linked with that kind of thinking. There would be a permanent job for Paddy Ashdown."
The issue is one that transcends traditional left-right divisions, however. Supporters of PR include Blair ultra-loyalist and Northern Ireland Spokesman Marjorie Mowlam, Robin Cook, shadow Foreign Secretary, and Clare Short, the women's spokesperson, from the "soft" left, along with left winger Ken Livingstone, Bill Morris, the TGWU's general secretary and hardline NUM president Arthur Scargill.Reuse content