Commercial broadcaster ITV revealed that net advertising revenues across the group dropped by five per cent during the first half of the year.
Its main channel, ITV1, saw ad revenues slump by nine per cent to £595 million during the six months ending June 30th.
But, announcing the drop in an unscheduled trading update, ITV revealed that those for its digital channels and breakfast show GMTV were up 24 per cent to £122 million.
ITV has been investing money in digital channels and popular websites such as Friends Reunited in order to reduce its reliance on advertising revenues generated from its flagship channel.
Despite the overall drop in ad revenues, the broadcaster remains confident that stability is now returning to the overall TV advertising market said by ITV to be down by an estimated 0.3 per cent compared to the first half of last year.
"Returning stability in the total TV advertising market has been an important feature of the first half, as has the improving schedule performance and the rollout of itv.com", said ITV's chief operating officer John Cresswell.
Nonetheless as ad revenues at ITV1 slumped in the first half, so too did viewing figures.
The channel's overall adult viewing share was down 4.7 per cent on 2006 figures.
However ITV stressed that in multi-channel homes alone viewing figures were only down by 2.5 per cent and emphasised that its digital channels, which include CITV and Men & Motors, continued to grow.
The broadcaster, which has acquired TV rights to show the Euro 2008 football competition in conjunction with the BBC, said that as part of plans to revitalise ITV1 a number of long-running programmes would be scrapped.
Among the programmes that proved successful over the first half was Britain's Got Talent, which saw an average audience of 11.6 million tune in for the final of the entertainment show where contestants competed to take part in the Royal Variety Performance.
ITV said its current £40 million cost reduction plans were also on track, while the results of a business review are to be announced later this year.
"Our business review is progressing well and I will announce the outcome of that process after the summer break," said ITV executive chairman Michael Grade.