Provoked by last week's TUC debate on the minimum wage, when Labour MPs were attacked for grabbing a large pay rise while denying a fixed hourly rate for the low-paid, a member of the Shadow Cabinet retaliated in kind.
Digging up the salaries of the union barons from the annual report of the unions' official Certification Officer, the incensed Labour frontbencher showed how far New Labour is prepared to go in declaring fratricidal war against the unions.
The man directly in the Labour firing line was Rodney Bickerstaffe, the Unison leader, who successfully demanded a minimum wage of pounds 4.26 an hour at last week's TUC.
He said such a rate would put full-time workers on about pounds 8,400 a year and, to rapturous applause among the 820 TUC delegates, Mr Bickerstaffe added: "I have said over and over again I am not attacking the rise for MPs. But if they are worth an increase of pounds 9,000 a year, how can they or anybody else deny to man or woman, black or white, young or old in this country, that amount for a full working year?"
The Independent's shadow cabinet source said MPs - including a dozen members of the Shadow Cabinet - had voted themselves a rise in salary from pounds 34,085 to pounds 43,000.
According to the Certification Officer's figures, he said, the Unison leader had received an increase of pounds 7,000 to pounds 71,000 in 1994-95, and the leaders of the Transport and General Workers' Union, the GMB general union and the RMT transport union were all getting pounds 50,000 or more last year.
A spokesperson for Unison said the Labour spokesman had his facts wrong. For his leadership of an organisation with a pounds 98m turnover, Mr Bickerstaffe was paid pounds 57,000 a year, not pounds 71,000, she said. The higher figure was paid to Alan Jinkinson, his predecessor. But the dispute between the two sides illustrated the degree of personal acrimony and bitterness that has seeped into relations in the Labour movement.
While Labour leadership sources are not displeased at the impression left behind by last week's rows, there is now an increasing risk of open warfare at the Labour conference, also in Blackpool, later this month. Certainly, there is scope for union-sponsored trouble on a number of sensitive spending issues like pensions and child benefit, and the Conservatives will be poised to exploit division.
It is one thing for Tony Blair to appear strong and in control, and distanced from the unions; it is another to open up civil war in the full glare of the media.
Recognising the threat posed by the latest Labour onslaught, Bill Morris, leader of the TGWU, said: "This sort of attack does not need to be dignified with a response."
John Edmonds, general secretary of the GMB, was also singled out for attack as a high earner, but in fact he argued against the pounds 4.26 figure, preferring a much softer resolution more to Labour's liking. Mr Edmonds has gone on record in the past saying that people on his level of salary should pay more taxes, but has since kept his own counsel on the issue as it became more sensitive.
The RMT leader, Jimmy Knapp, has been on a salary of pounds 43,000 for the past three years. He said the logic of the frontbencher's argument was that if union officials were paid more than their members they should not be representing them in pay negotiations. "There is a good old trade- union adage that you should be paid the rate for the job and that should apply at the top of an organisation and at the bottom," he said.
A spokesman for the TGWU said that Mr Morris's salary was public knowledge and so was the union's record of fighting on behalf of the low-paid. "Politicians would do better to address the scandal of low pay rather than indulging in cheap attacks."
Top Union Leaders' Salaries
Unison: Rodney Bickerstaffe pounds 71,000
TGWU: Bill Morris pounds 53,000
GMB: John Edmonds pounds 55,000
NUM: Arthur Scargill (president) pounds 55,000
RMT: Jimmy Knapp pounds 50,000
Source: Annual report of the Certification Officer 1995