If the impasse is not resolved, then Unilever ads could disappear from television schedules on stations other than ITV, with which the FMCG giant has an existing deal.
In order to continue to meet the ITV deal and deliver the savings promised to Unilever, MindShare is increasing the pressure on the other commercial broadcasters ahead of the start of Unilever's new trading season at the beginning of next month.
Unilever signed a four-year £320 million agreement with Carlton and Granada in May 2002, which promised ITV a 57 per cent share of its ad revenue.
Insiders have said that an impasse has been reached between MindShare and ITV's rival TV stations - most notably Channel 4, five and Sky Media - as they try to reach an agreement before the 1 April deadline.
Nobody at MindShare was available to comment.