There could be more time to make the tea in the middle of Coronation Street if Ofcom agrees to follow the lead of Europe and relax the rules governing television advertising.

ITV1, Channel 4 and Five are all restricted to showing seven minutes of advertising an hour on average during the day, compared with 13 minutes typically shown on American networks, where a break after the introductory credits is common.

But Ofcom, the communications regulator, is preparing to review the rules and has hinted that it is likely to allow more minutes of advertising on British screens. It could permit up to 12 minutes an hour, the future European maximum.

Steve Roberts, head of the competition group at Ofcom, told an audience of City analysts that a review of the rules was imminent. He said that “a significant relaxation will broadly benefit public service broadcasters” — referring in this instance to ITV1, Channel 4 and Five, Britain’s most popular commercial channels.

Insiders at the regulator are keen to emphasise that they want to avoid coming close to US advert levels, which they believe would be unpalatable to British audiences. Instead, the most likely outcome of the review is that the three channels will be allowed to show nine minutes per hour of advertising, a 28.5 per cent increase. That would put them on a par with digital channels, where in a long-standing concession to the less popular broadcasters, a nine-minute average is the norm.

Azon Howie, of the Carat advertising agency, said: “There will always be complaints if a change like this is introduced, but if we’re allowed to do it people will be keen. At first it will drive down the price of television advertising, but gradually the extra advertising available will make television more popular compared to newspapers, magazines and other media.”

Television advertising is worth £3.47 billion in Britain, and a 30-second commercial in a programme such as Coronation Street or during a big sports tournament can cost about £50,000. But, despite the scale of the advertising industry, commercial television has taken a battering since the middle of the decade.

A two-year downturn in the market, coupled with a particularly poor period for ITV in its never-ending battle with the BBC, has cut spending. At the same time, the industry has been hit by a series of other restrictions, most notably Ofcom’s decision to ban “junk food” advertising from children’s programming, and other shows popular with children such as Hollyoaks and The Simpsons.

Yet, while the chance of selling more adverts is attractive, broadcasters are also nervous. The three commercial broadcasters are all reluctant to talk about the subject publicly for fear of upsetting the regulator at a sensitive time, but one big broadcaster indicated that it would be cautious about greatly increasing the amount of advertising it showed.

The review of the rules follows the passing of a European directive, which comes into force at the end of the year. That sets a baseline for all members of the EU, and previously restricted all broadcasters to nine minutes an hour of advertising. Britain, though, chose to adopt slightly stricter rules for ITV1 and Channel 4.

The new directive, though, permits broadcasters to show 12 minutes of advertisments an hour, taking Europe close to the American norm. As it comes into force from 2008, Ofcom has decided it is time to look again at Britain’s rules, and thereby increasing the length of the beverage break.

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