ITV is braced for a severe decline in autumn advertising revenue as household-name companies batten down marketing budgets before Christmas.

The broadcaster's advance deadline for September advertising bookings passed yesterday and agencies said that they expected that ITV1, Britain's most-watched commercial channel, would face a 13 per cent drop.

ITV, headed by Michael Grade, has so far managed to weather the economic storm but September is a critical month because it acts as an early barometer for how willing advertisers are to spend on promotion in the run-up to the festive season.

“Companies are thinking about what is happening in the next few months - and it is obvious that there is general concern about the state of the economy,” a senior media buyer said.

ITV is due to air of some of its strongest properties in September, with The X-Factor designed to gather momentum on Saturday nights and a series of new drama launches. Among them is Britannia High, a musical drama along the lines of Disney's High School Musical, with songs written by the Take That singer Gary Barlow.

However, even a strong on-screen schedule can only marginally offset a weak economy. Since Mr Grade arrived at the beginning of last year ITV's share price has fallen by two-thirds because of the near-continuous deterioration in advertising.

The shares lost another 2.9p yesterday - or 6.8 per cent - to close at 40.1p as rumours about the figures began to circulate around the City. Would-be bidders, though, have struggled to raise finance to mount a bid, even as ITV's value has plunged.

Channel 4 is also braced for a difficult month because the Big Brother broadcaster works on the same booking timetable as ITV, which faces a tough comparison with last year. This time last year ITV was the only broadcaster showing the Rugby World Cup, which proved attractive with prestige advertisers.

The weak bookings indicate that the softness in advertising is spreading across the media. Trinity Mirror, which owns the Daily Mirror, said last week that advertising across its titles had collapsed by 12.6 per cent in May and June and several newspaper groups are privately reporting poor figures.

ITV had been performing better, with bookings down 2 per cent last month and 4 per cent for the traditionally quiet months of July and August but there have been fears that at some point revenues would contract sharply.

Its leading clients have traditionally included supermarket groups such as J Sainsbury, Asda, Tesco and Morrison as well as car companies, consumer goods firms and utilities.

ITV declined to comment but a spokesman said the broadcaster had produced the top three most-watched programmes this year - Britain's Got Talent, Dancing on Ice and Coronation Street - and six out of the ten most-viewed shows on all channels.

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