Senior Tories fear that Tony Blair will try to exploit the Prince of Wales's wedding by announcing just a few days before the nuptials that a general election will be held on 5 May.
Ministers believe Mr Blair will announce polling day on Monday, 4 April. There would then be a scramble to rush Bills through Parliament, which would be prorogued on the Thursday, the day before the wedding.
News of the wedding has, however, killed off the prospect of an election before 5 May. There has been speculation about a March or April poll to capitalise on Labour's opinion poll lead, but ministers said the campaign could not coincide with the build-up to the wedding.
The Tories suspect Mr Blair has orchestrated the timing of both events. One Shadow Cabinet member said: "It was clearly part of the spin to try to give Blair a feelgood factor."
Ministers denied the charge, saying that the election campaign would not start until the week after the wedding, which would take place during a brief "political pause". One Labour official admitted, however, that the timing of the wedding was "remarkably helpful".
Downing Street said the Prime Minister had known about the wedding plans "for some time". Mr Blair's official spokesman said: "He only told a very, very few people - less than the fingers of one hand."