Loud cheers rang out among ITV executives when Jonny Wilkinson drop-kicked England to World Cup victory. Their joy was not prompted by national pride alone.

They had another good reason to celebrate. The final was part of an international rugby package that has delivered unexpectedly large audiences of the type - young and male with money to spend - much sought after by advertisers, the people who, after all, pay ITV's wages.

What's more it was purchased for what many consider the bargain price of £40m, adding up to what's been called "the broadcasting coup of the year".

But, whether this ratings success, achieved on a tidal wave of English pride can change the on-off relationship between viewers and sport is unlikely.

People will watch in their millions when their home country is involved, and for England this is rare enough to make even the mere possibility of a win the cue for everyone to get over-excited and raise the Union Jack. Once the team or individual comes a cropper, everyone reaches for the off button. Is anyone for tennis after Henman is knocked out?, you have to ask.

Buoyed up by Jonny and his team's victory, ITV sports bosses can afford to forget the erratic viewing habits of the British public, at least for the time being. The cost of buying the rights for the 2003 and 2007 tournaments has more than been repaid by higher advertising rates and big audiences.

The audience for Saturday's final peaked at nearly 15 million, an unprecedented figure for a morning programme."It is fair to say we're pleased," ITV Sport's communications director Steve Double commented with masterful understatement.

"We always knew the numbers of viewers would increase as the tournament went on, particularly if the home nations did well. Rugby is never going to attract the same figures as football, that's a fact, but it does deliver the sort of audience advertisers love."

ITV would dearly like to say it was all planned, although they actually saw the 2003 tournament as a means to an end - the 2007 tournament being staged in a more viewer-friendly time zone, France.

They thought the time difference with Australia for this year's tournament, resulting in matches being played before noon our time, would be a turn-off for audiences.

ITV bosses were helped by the BBC making an offer that international rugby board officials were well able to refuse, and instead went looking for something more reasonable from ITV.

The gamble paid off, with ITV signing a two-tournament deal. With ad revenues down, any means to attract viewers beloved by advertisers was worth the risk. What they couldn't foresee was the British viewing public's willingness to lounge in front of the box on a Saturday morning to watch something that wasn't aimed at children.

"It was spellbinding television with a sensational climax and it capped seven weeks of brilliant live rugby action," said ITV Controller of Sport, Brian Barwick.

It certainly worked better than the attempt to outdo the BBC over football by snatching the rights and promoting coverage of The Premiership to peaktime Saturday ITV. Presenter Des Lynam, poached from the Beeb for the occasion, was left with plenty of matches to screen but fewer and fewer viewers interested in watching.

Poor ratings led to that soccer programme being sent off permanently, while the collapse of ITV Digital did nothing to restore faith in ITV's sports coverage. The Rugby World Cup has provided a welcome fillip to its sporting fortunes. Even the BBC will benefit. The raising of Jonny Wilkinson to superstar status means he's almost guaranteed to walk off with the BBC Sports Personality of the Year award, to be presented on BBC1 in a few weeks time.

Evidence of the fickleness of viewers came quickly. By Tuesday, the sport has switched from rugby to football. But EastEnders and Holby City on BBC1 beat ITV1's Champions League Live coverage. Arsenal's 5-1 victory over Inter Milan was no match for Dirty Den's scheming to frame Phil Mitchell and a killer nurse on the wards in Holby hospital.

How different to ratings from the Rugby World Cup final, which came close to beating the audience that watched England's World Cup quarter-final clash against Brazil last year.

Saturday's game was still only the second highest ever audience for an international rugby match in the UK. The top spot is held by coverage of the 1991 final. Then, the outcome couldn't have been more different, with Australia beating England.