Virgin Media has lodged a complaint with Ofcom, aimed at halting the BBC-backed video-on-demand service Project Canvas. The cable giant says the project, which is developing common standards for net TV in the UK, is anti-competitive. BT, Channel 4 and ITV are also partners. It was given the green light in May, when the Office of Fair Trading ruled it was not a merger. But Virgin Media said it could destroy the online TV market. It said the collaboration between the three most prominent public service broadcasters would "significantly and irreparably harm" the TV sector.