A report from Zenith Media is expected to predict that overall UK advertising spending will fall by 0.8% this year, and ITV is expected to see revenues fall by 8.9%.
Zenith had earlier predicted that advertising would grow by 3.6% this year, despite the slowdown in the US. Now, the company says that the downturn in UK newspaper and television advertising is been worse than expected and hopes of a recovery in the second half of the year have been dashed.
Zenith's gloomy predictions came as Granada, which is one of ITV's main shareholders, made an appeal to the government for help in changing media laws.
In a letter to Tony Blair, leaked to the press over the weekend, Granada warned of job losses and foreign takeovers unless media laws are changed.
It appealed for the government to allow Granada to merge with Carlton Communications, the other main owner of the ITV network, in order to fend off potential foreign takeovers.
The falling share price and declining advertising revenues mean that Granada could be vulnerable to foreign approaches. Earlier this month, it said that its ad revenues had slipped by almost 11% in the nine months to June, and it predicted a fall of 17 to 18% in July. The share price dropped another 4% this morning to 142p.
The leaked letter also indicated that ONdigital's future was under threat unless the government announced a date for switching off the analogue broadcast signal - forcing viewers to buy digital TV sets.
Granada spokespeople have refused to comment on the correspondence or confirm its authenticity.