Leading article: Finally, an electoral opening for three-party politics

The debate gave Nick Clegg his chance – and he took it with aplomb

In agreeing to take part in the first-ever televised election debate, the UK's main party leaders were only catching up with most of the rest of the democratic world. Still, public scepticism about the desirability, even usefulness, of such an occasion abounded. In the event, there were three convincing winners from Thursday night's event – and we don't have in mind all three candidates.

The first winner was the debate itself. Britain's leading politicians showed themselves as adept at debating as those of any other country – in some respects, more so. Contrary to widespread fears, the heavily regulated format did not prove stultifying. As interpreted by ITV's Alastair Stewart, proceedings moved along at an impressive clip, and the three leaders – tempered perhaps by their regular encounters at Prime Minister's Questions – were soon engaging each other.

As a country, we may have come late to the election debate, but we have shown that we can do it as well as anyone. The viewing figures were not as high as some had hoped, but, at 9.4 million, by no means as low as feared. Even if fewer people tune in for next week's debate, on international affairs, forecasts that this election would be marked by deep-seated and irremedial public apathy are already wrong.

The second winner was, undoubtedly, the leader of the Liberal Democrats, Nick Clegg. It is true that Mr Clegg had most to gain from the format that gave the third party a seat at the top table – or rather a lectern on the stage – on equal terms with Labour and the Conservatives. But it was up to him to make the most of it, which he did with energy and aplomb. He showed himself to be the equal of the other two in his familiarity with the policy questions, and superior in his capacity to communicate with the audience.

This triumph is significant for Mr Clegg personally, as well as politically. Until now, the Liberal Democrat leader seemed in danger of being overshadowed by the party's genial star and Treasury spokesman, Vince Cable. That is no longer so. Of course, Mr Clegg has a much more difficult task next time round; he will have this performance to live up to and expectations will be even higher. But a poor showing in the first debate would have given him the hard task of making up for lost time. As it is, he has put himself and the Liberal Democrats very effectively on the electoral map and – just perhaps – allayed some of the trepidation about a possible hung Parliament. If so, that would be all to the good.

The third winner, though it might seem surprising to say so, was the Prime Minister, Gordon Brown. While, in our judgement, Mr Brown was the runner-up in this debate – although well behind Mr Clegg and only a little ahead of the Conservative leader, David Cameron – it is the Labour leader who emerges as the chief beneficiary in electoral terms. And it is, after all, only the election that matters. Mr Cameron's uncharacteristically stiff and nervous performance left Mr Brown unchallenged in appearing prime ministerial, even if some Conservative policies – regrettably, these included immigration – were received favourably in simultaneous polling.

Mr Brown was, for the most part, his lugubrious, analytical self. But he succeeded in two necessary objectives: not to be bested by Mr Cameron, and to do nothing that would exclude the possibility of some sort of post-electoral alliance with Mr Clegg. He managed both, even if his periodic affirmation, "I agree with Nick", sounded just a little strained. Mr Clegg's strong performance, if he can sustain it, also has the capacity to help Mr Brown, by strengthening the Liberal Democrats in marginals against the Conservatives. In helping his own party, it could be said, Mr Clegg also did Labour and Mr Brown a good turn.

So this first televised debate was not a lost opportunity: not for Mr Brown, nor for Mr Clegg, nor – more to the point – for the voters. The only loser was Mr Cameron, to whose strengths, paradoxically, the debate format was expected to play. But there are still two encounters where he has a chance to find a more compelling voice and the outcome then could be different. What this first debate has done above all, however, is to open up the campaign as a genuine three-party contest and thus increase the prospect of the hung Parliament this newspaper would favour. That is not bad for 90 minutes' work on a Thursday evening.