SMG, Ulster Television and Channel Television are refusing to carry any promotions for ITV Digital, which is being launched today with an advertising campaign.
The companies, which own ITV licences in parts of Scotland, Northern Ireland and Jersey and Guernsey, are considering taking legal, which could see their lawyers apply to the courts for an injunction to block Carlton and Granada's rebranding plans.
The issue of ownership of the ITV brand, however, unclear. There is doubt over whether the brand is owned collectively or whether each company controls the brand in the area it broadcasts.