Made up: Channel 4 and WPP end advertising stand-off

Channel 4 has ended a dispute with its biggest advertiser, WPP, that was costing the state-owned broadcaster up to £5m a week.

The sides agreed a new deal today, meaning that WPP's clients will start advertising again on C4's portfolio of channels.

WPP's media-buying arm, Group M, which spends upwards of £250m a year with C4, pulled all its ads from 1 January, after a previous two-year deal ran out.

Relations between C4 and Group M over the price of airtime broke down last month. While such negotiations are often tough, it is rare for a media agency to pull all its ads. In a joint statement, C4 and Group M said: "Negotiations are necessarily long and complex when two major media companies want to agree commercial terms in a complex and fast-moving environment." they said.

Group M's clients include Barclays and BSkyB.