FIVE years ago, when Neil Kinnock challenged John Major to a series of television debates during the 1992 election campaign, he was dismissed with a snub. “Every party politician that expects to lose tries that trick, every politician that expects to win says no,” declared Mr Major.

How times change. Running 26 percentage points behind in the polls only six weeks before an election, Mr Major has accepted Tony Blair's challenge to a televised debate. A measure of the prime minister's pessimism over his election chances is his eagerness to participate in what he described scornfully less than a year ago as “a stupid PR stunt”. The last incumbent of 10 Downing Street willing to engage in a television debate was Jim Callaghan in 1979, just before going down to one of Labour's worst post-1945 defeats. His offer was rejected by Margaret Thatcher.

This time the chance of holding Britain's first televised election debate between the party leaders looks brighter. Mr Blair may have little to gain from such an encounter, but says he is keen to take part. However, hurdles remain. Mr Major refuses to debate directly with Paddy Ash down, leader of the Liberal Democrats, arguing that only he himself and Mr Blair have any chance of becoming prime minister.

In an attempt to meet Mr Major's objection, both the BBC and ITV have come up with what they are calling “a sandwich formula”. Their rival plans are similar. Brief opening statements by all three party leaders would be followed by a debate between Mr Major and Mr Blair. Then a short interview with Mr Ashdown alone, conducted by a broadcast journalist, probably one of the Dimbleby brothers, would follow. The programme would end with a second 30-minute debate between Mr Major and Mr Blair with cross-questioning by journalists.

The Lib Dems understandably consider this plan unfair, and the party threatens to appeal to the courts to prevent it. “Basically it's Ashdown in a cupboard while the big boys play in the open,” says Lord Holme, a close adviser to Mr Ashdown. The BBC originally proposed a debate between all three party leaders but it changed tack when ITV bowed to Mr Major's refusal to share a platform with Mr Ashdown.

Many people argue that there should be a proper televised debate involving all three big-party leaders. This is not a presidential race; it is about electing a government and, however low their standing in the opinion polls, the Lib Dems have a right to participate directly in any debate for a number of reasons.

They are the main challengers to the Conservatives in more than 150 seats. They have a strong position in local government: they run four times as many county councils as the Tories. The formula of past elections in which the Lib Dems have been allotted broadcast time on a 5-5-4 formula, giving them almost full equality, has worked well. A recent Gallup poll found that 82% of respondents wanted a debate in which all three party leaders take part. If Mr Major listened to what the public wants rather than his advisers in Conservative central office, the technical problems would soon disappear. Kenneth Clarke, the chancellor, has already indicated his willingness to engage in four televised debates with his Lib Dem and Labour counterparts.

The rivalry between BBC and ITV has made both networks unnecessarily craven before the prime minister. If they stood up to Mr Major, there is little doubt who would cave in. It was Mr Major, after all, who first called for a televised debate. In any case, he cannot now afford to be seen to be sabotaging the whole idea. The failure of the two broadcasting networks to insist on fulfilling their legal obligations to achieve a balance between the main parties makes the case for an independent electoral commission to oversee such matters.

The argument about the format of the debates may be generating a lot of heat this week but, ironically, it is doubtful whether the debates themselves will change many votes, however they are done. Gladiatorial contests make great copy. The gaffes surrounding such debates have become part of the folklore of American presidential elections ever since Richard Nixon's five o'clock shadow is said to have lost him the 1960 presidential race. Since then there has been Gerald Ford's blooper in 1976 that “there is no Soviet domination of Eastern Europe” and Ronald Reagan's effective put-down in 1980 of Jimmy Carter: “There you go again”.

And yet, despite the widely held view that these incidents swayed votes, there is remarkably little academic evidence to suggest that they did. A study of televised leaders' debates across the world published on March 20th by the Hansard Society, an independent parliamentary research group, found little sign of it.

Debates, the report suggested, at best intensify voting intentions among the weakly committed; but this, be it noted, is usually relevant only in a close-fought election. Other studies have found that debates have some effect on how candidates are regarded, and on voters' preferences, but these effects have been small and brief. Significantly, those who failed to watch debates were often just as influenced as those who did. That suggests that the media's verdict on which candidate won may be almost as important as what was actually said. Televised debates almost certainly help third-party candidates, such as Ross Perot in America, by giving them greater exposure, which is most likely the real reason why Mr Major does not want to include Mr Ashdown.

Anyway, transferring American experience to Britain can in this aspect of politics be a dangerous business. British politicians are much more accustomed to the cut and thrust of face-to-face debate. The twice-weekly jousts between the prime minister and the opposition leader in the Commons mean that both have had years of practice in the art of the sound-bite. The idea that in a formal television debate either Mr Major or Mr Blair will be exposed to millions of viewers as “Weak John” or “Phoney Tony” is hard to believe. More likely, both men will be so smooth and well-rehearsed that they will put voters to sleep.

A three-way debate including Mr Ashdown would not only be fairer; it might also produce a much livelier encounter.