Channel 4 and five will merge their sales operations if Carlton and Granada get the go-ahead to form a single ITV, according to the Sunday Times today.

One source said: "The conversations have moved on from ‘what if?’ to ‘when and how’. I think if the ITV merger goes ahead, a single sales house for the other television players is inevitable."

Another 'senior' source told the newspaper: "If there was one ITV, we would put Channels 4 and 5 together the following day. We would have to do it to protect ourselves. If they let a single ITV go through with more than a 50% share of the market, the competition authorities could not refuse to have a combined Channels 4 and 5 facing it. Our combined market share, after all, is less than ITV’s."

The report also claims that the pair would be keen on involving BSkyB in such a deal.