The 750,000-strong union, which has a reputation as Tony Blair's "pet" union because of its unstinting support for New Labour policies, has emerged as the surprise leader of the growing opposition to PR.
It will fund a campaign to rally support at the TUC Congress and the Labour Party Conference next month. It will also financially underwrite PR opponents in Parliament, a cross-party coalition of MPs known as the First-Past-The-Post Group.
The issue of PR will come to the fore in October when the government- appointed commission on PR, headed by Lord Jenkins, is expected to recommend that future elections are fought under such a system. Labour's general election manifesto commits the Government to holding a referendum on the issue.
A war chest of pounds 10,000 has been set aside for the campaign and an AEEU spokesman said it was "throwing down the gauntlet" to those whom it believes are plotting to reinvent British politics. More cash will be made available if necessary.
While the Labour Party's National Executive Committee has signalled that it opposes PR, powerful elements within the Government believe a political revolution can be achieved by changing the voting system.
PR, they say, would allow for a fundamental realignment of British politics, in which a grand coalition of radicals - including left-wing Conservatives, Liberals, who have long argued the merits of PR, and New Labour modernisers - would gather under the same banner. PR would sound the death knell of the confrontational nature of the traditional two-party system, say its supporters.
Political big-hitters who back PR include Robin Cook, the Foreign Secretary, and Peter Mandelson, recently appointed to the Cabinet as Secretary of State for Trade and Industry. The Prime Minister is said to be neutral on the subject.
However, the role of Lord Jenkins at the head of the commission is highly significant. The former Labour home secretary, who went on to help found the Social Democratic Party, is a highly influential member of Mr Blair's inner circle of friends. Observers say he would not have been appointed if the Prime Minister was not serious about electoral reform.
PR already exists for the new assemblies in Scotland, Wales and Northern Ireland and it is believed that Lord Jenkins will recommend a measure of PR be grafted onto the existing British electoral structure as a first phase. Full-scale PR would follow afterwards.Reuse content