Mr Dromey, Ms Harman's husband, yesterday declared that he is to stand against Bill Morris, general secretary of the TGWU since 1991, when Mr Morris submits himself in June for re-election, as he is periodically obliged by law to do.
The T&G has never faced anything quite like this audacity before. For decades the standard bearer of the left, relations between the country's second-biggest trade union and the Labour Party have always been tense. Mr Dromey's success in capturing the leadership of Labour's largest union affiliate would deliver an important element of reliability to the Labour leader. The disappearance of headlines like "TGWU snub for Labour", "TGWU votes for Clause IV", is a very attractive prospect for the Labour leadership.
In the union's heyday of the Sixties and Seventies, T&G general secretaries such as Frank Cousins and Jack Jones were better-known public figures than half the Cabinet. There is more than a hint in the tone of Mr Dromey's campaign statements yesterday that he hankers after such prominence - both for himself and the union - again. He says he wants to lift the union from its present 914,000 membership, back up to its pervious high point of 2 million by the end of the century. His strategy for growth is to win new members and negotiate mergers.
As national secretary of the public services trade group, one of the largest and best organised within the union, Mr Dromey, 46, has run high- profile campaigns to save jobs in the defence industry and to support members in local government threatened with compulsory competitive tendering. He is a skilful operator in his dealings with the media and will stress the youth and vigour of his bid. His election slogan will be for a modern union with a modern image and modern leader.
In launching his campaign yesterday, he carefully steered his way around the political pitfalls of being allied to Mr Blair's fortunes: "It's because I am close to the Labour Party that I have a strong sense of the proper measure of the relationship," he says. "They are the political party. We are a trade union. We need a relationship of integrity but if our interests do not coincide, I will always put the members first."
It is not immediately evident what has prompted this challenge right now - indeed, when Mr Morris was elected four years ago his victory was particularly welcomed for giving Britain its first black union leader. Mr Dromey maintains it has not been an easy decision to stand, but is clear that he is seeking both organisation changes within the union and a shift in its relationship with the Labour Party.
He is frustrated by the fact that Labour's biggest affiliate is always one of the last to accept the policy changes demanded by the modernisers. It has been too long on the losing side of important party votes and thus has lost influence with Labour politicians.
As well as the difference in political outlook, there has been criticism of Bill Morris's performance; in particular lost opportunities to create effective mergers. The GMB general union has scooped up several small textile unions, the railway union picked up the seamen and Ucatt, the building workers union, has failed so far to be tempted. The T&G lost its "biggest union" label after the merger of the three public sector unions to created the 1.3 million member Unison.
Nevertheless, Bill Morris must start the race as the clear favourite. He is well-known within the union, has the advantage of four years in the job and the backing of the left-wing machine. But Jack Dromey has the ability to make this an extremely close contest by picking up every vote cast against Mr Morris. And this will not be a straightforward left- right fight, either.
By law, the vote has to be conducted by full postal ballot. But the recommendations from powerful regional committees are central to success with each of the eight regions likely to declare support for one or other of the candidates. So activists are still important power-brokers. Bill Morris won in 1991 with the support of the broad left, the largest and most influential group. Many of these will be unlikely to switch allegiance to one they see as a right-winger in the pocket of Tony Blair. They are also acutely conscious of the political incorrectness of unseating arguably the most influential black man in Britain.
Mr Morris, 57, is also quite happy to exploit another moral dilemma for any left-winger thinking of voting for his opponent. "To be honest it was not expected within the union that anybody would use the Tory law to try to unseat an incumbent general secretary," he says. "But it's a democratic union and anybody has the opportunity to stand."
Others in the union, however, will welcome the emergence of a plausible contender to Mr Morris. The North-west region, one of the most militant, is expected to back Mr Dromey, in protest at an unpopular reorganisation. The Irish region is also likely to come out in his favour, while many left-wingers were unhappy with the way Mr Morris flirted with the ideas of Clintonism.
Mr Dromey will also find support for his belief that true political influence within the Labour Party can be best achieved outside the smoke-filled rooms and conference chambers, and away from wielding the block vote. "Less time at the table of high politics and more in the workplace" could be a vote winner.
In 1992, when Dromey stood for deputy general secretary, he ended up only 11,200 votes behind Jack Adams, the candidate of the broad left, despite not having any recognised powerbase or grouping co-ordinating his campaign.
Both men will tell their members that the election is about the union, not politics. To a degree, they are right. But at the heart of the debate is politics, about taking the T&G to the centre of Labour's thinking. In new Labour, the emphasis is not about block votes and big conference performers but about developing new strategies for the market-driven world of work in the next century.
If Tony Blair becomes Prime Minister, he will want to be sure from the start of one thing: that there is no chance of a repeat of the conflict seen during the winter of discontent which destroyed the last Labour government and meant 15 years in the wilderness.Reuse content