With Downing Street still reeling from the slump in Labour's "core vote" at the Euro elections, John Monks warned that the difficulties in the heartlands would simply "intensify" at the general election if the party kept concentrating on wooing its new middle-class voters. "Labour too often seems embarrassed by its traditional supporters and what they believe," he said.
The TUC General Secretary is one of the Prime Minister's closest allies in the union movement. But he finally lost his patience with the Government in the wake of the European election.
"I always understood the new support was meant to be in addition to Labour's traditional support," he said. "The worrying Euro election results shows a real danger that some of it may now be at the expense of core support."
Mr Monks's words were in sharp contrast to a speech by Peter Mandelson last week. The former Trade and Industry Secretary told a fund-raising dinner on Tuesday that it was "baloney" to suggest that the Government needed to focus attention back on its traditional blue-collar voters and insisted that the coalition between old and new support was essential for victory.
However, Mr Monks reflects the private views of several members of the Government, including Peter Hain, the Welsh Office minister, who recently accused Mr Blair of concentrating too much on Daily Mail readers at the expense of people who took The Mirror.
According to his allies, Mr Blair is deeply concerned that Labour's traditional supporters appeared to abandon the party in the poll on 10 June. The crisis in the "core vote" is one of the main issues concerning party strategists as they examine what went wrong. In seats where Labour had a lead of 20 percentage points or more at the 1997 general election, its vote fell by 22 points, compared with only 9 per cent in Tory constituencies.
As part of a drive to combat inertia in the run-up to the next general election, the Prime Minister has instructed his ministers to become much more political in their speeches and announcements. He told the Cabinet last Thursday that one of the main lessons of the European election defeat was that Labour had to return to aggressive partisan politics. Ministers should start attacking the Tories rather than just concentrating on the details of policy, he said. They should also speak about the "Labour Government" when doing media interviews, rather than simply referring to the institution of the "Government".
Mr Blair issued the same message at a meeting of senior strategists in Downing Street on the day after the country went to the polls. "The Prime Minister wants all ministers to remember they are not just there to run their departments, but to get out their and sell what New Labour has done," a Downing Street source said. "You are going to see a much more political drive to the Government."
Ministerial special advisers were also ordered at their weekly meeting on Friday to do more to get the party's message across. Informal links between Government departments and the party machine are to be strengthened. This emphasis will renew Tory accusations that Labour is seeking to politicise the Civil Service, which is meant to be neutral.
In his speech at a Fabian Society/New Times seminar, Mr Monks criticised spin doctors' promotion of right-wing policies. "The emphasis is always on the new," he said. "It sometimes seems as if those of us who voted Labour before the 1990s are being accused of poor judgement, or seen as embarrassing elderly relatives at a family get-together."