Multinational outdoor media owner CBS Outdoor has given notice to London Underground of its intent to terminate its display advertising agreement three years early on March 31st 2012, unless the two parties agree to new terms.

The dispute involves CBS Outdoor's claim that installation of escalator screens and platform projection spaces have been delayed by Transport for London's (TfL) own construction projects and is suing London Underground for tens of millions of pounds in damages.

CBS Outdoor's threat to terminate ad support would take effect just months before the London Olympic games begin – an event likely to increase the value of advertising real estate across London.

The two companies are already fighting a separate legal case over how to split advertising revenues on the eight-and-a-half-year contract they signed in 2006.

London Underground claims it has met all of its obligations to date and that any delays to CBS Outdoor's Tube development projects due to changing circumstances after the 2008 financial crisis or otherwise are the responsibility of CBS Outdoor.