Talks between the two broadcasters have taking place for some time but it has been reported that terms for a deal have been agreed.
A Channel 4 source said: “Channel 4 and Sky’s sales teams are to merge. Andy Duncan, [C4’s chief executive] wanted a deal to go through and has been leading the Sky talks with Andy Barnes [C4’s sales director].
“The merger will allow both companies to make huge savings, lower headcounts and run a more streamlined operation. There is unrest at Channel 4 about this decision.”
Potential synergies between the two companies could see the headcount of both sales teams cut by 50pc.
Both C4 and BSkyB declined to comment. However, it is understood the broadcasters are unwilling to announce the joint venture until the Competition Commission publishes its recommendations about regulations governing ITV’s advertising sales in six weeks.