Concern about potential electoral fraud in Thursday's election was mounting last night, as Mr Tony Blair and Mr William Hague ignored the opinion polls and declared it still wide open.
Buoyed by the defection of a former Conservative Treasury minister to Labour, in opposition to Tory policy on the euro, the Prime Minister appealed to "decent One Nation" Conservatives to abandon Mr Hague.
Mr Hague vowed to "teach Labour a lesson" and leave the media "surprised" come Friday morning, as he unveiled his blueprint for the first days of a new Conservative administration.
And Mr Charles Kennedy tacitly endorsed tactical voting, as he predicted an imminent Tory "civil war" and again insisted only the Liberal Democrats could provide a second-term Blair government with effective opposition.
Mr Blair defended new regulations designed to boost postal voting while saying any irregularities would have to be investigated.
However, Mr Kennedy raised the nightmare prospect of Florida-type disputes as concern built about the possible abuse of the postal voting system following an expose by BBC Radio's Today programme.
A reporter on the programme yesterday revealed how he had obtained a total of seven votes - enough to have reversed the result in the last election - in Britain's most marginal constituency, Torbay in Devon.
Applications were made in the names of deceased persons taken from death notices in the local Herald Express newspaper, and sent by the authorities to the addresses of staff working on the programme.
Under the new rules people are not required to provide a reason for seeking a postal vote, and are entitled to have their postal vote sent to any address, rather than that at which they are registered to vote.
The programme stressed it was not making any allegations against any of the participants in the Torbay contest, where the Liberal Democrats are defending a majority of just 12 over the Conservatives, from whom they gained the seat in Mr Blair's 1997 landslide.
However, its investigation revealed the seeming ease with which electoral malpractice of a kind often associated with elections in Northern Ireland could now be imported to Britain.
The revelation came just 24 hours after a Mail on Sunday investigation raised questions about the high incidence of postal vote applications - 25,000 - in Stevenage in Hertfordshire.
Mr Blair said it was "very important that we enfranchise as many people as possible" and described the new rules as "a thoroughly good thing", while saying any irregularities would have to be fully investigated.
However, Mr Ken Ritchie of the Electoral Reform Society said if the number of postal voters was rising from around 2 per cent to perhaps as high as 20 per cent, "it doesn't need many of them to be dodgy" to affect the outcome. Mr Ritchie said that if the number of postal votes was significantly higher than the margin between the two leading candidates, he would expect to find defeated candidates checking the register of deaths to establish that all the votes had been validly cast.
Mr Kennedy said such a development would be "sickening" given that "we all had a good laugh at the American situation in Florida" at the conclusion of last year's presidential election.
Mr Kennedy yesterday said commentators should be careful about "using this term tactical voting as if it is a second-class vote." The first-past-the-post system was a corruption of individuals' wishes, he said, and people who voted tactically only did so "after thinking very carefully".