They have accused ITV of attempting to lessen the decline in its advertising revenue by adding in money from group companies. ITV, which has seen its share of audience decline with a disappointing performance from its current schedule.
In particular, the broadcasters have identified the use of the Letts Educational brand, which publishes study guides and educational literature and is part of Granada Learning, in an ITV campaign. The additional money could improve ITV's revenue figures and, therefore, artificially alter its airtime prices.
Agencies, however, have said the broadcasters are over-reacting and that the sums of money involved on the Letts campaign are too small to make much of a difference to station prices.
One agency broadcast director pointed out that other TV stations also use sister brands, such as Sky's current campaign for its Sky credit card, to inflate their prices, but added that they would monitor the situation closely.
The complaint that some broadcasters use campaigns for brands within the holding company portfolio in such a way is not a new one. Before the ITV merger, Carlton and Granada were both criticised by the IPA for using revenues from their sister companies, such as Ask Jeeves and Jamba, to "harden" the market.
ITV's crucial Saturday schedule has been hit by the disappointing performance of 'Celebrity Wrestling', which was dropped halfway through its run despite receiving extensive marketing support.
ITV is pinning its hopes on 'Celebrity Love Island' proving as successful as 'I'm a Celebrity... Get Me Out of Here!'. However, early indications suggest that audiences are tailing off.
If you have an opinion on this or any other issue raised on Brand Republic, join the debate in the .