YouView, the BBC-backed internet-connected TV-on-demand service, has been delayed until 2012.

The venture, which was formerly known as Project Canvas, will see internet-connected set-top boxes offering seven days worth of catch-up TV, along with free archive shows, apps and widgets. TV providers signed up to take part include the BBC, ITV, Channel 4 and Five, while UK ISPs TalkTalk and BT are also on board.

The service, which has already been delayed once, was expected to be officially launched to consumers later this year. However, a number of setbacks, including the departure of Anthony Rose, project's chief technology officer, has meant the project has suffered further delays.

Richard Halton, CEO of YouView, said: "Our focus has always been to deliver a product to consumers that is right, but not rushed. Creating a truly open TV platform that will bring consumers increased choice has required significant technological innovation. Our timings for the launch reflect the scale and complexity of this project."

Last year, rival broadcaster Sky lodged complaints with regulator Ofcom about the service. Sky was thought to have raised concerns over the effect YouView will have on competition - in particular that members of the project will be unlikely to create innovative TV-on-demand services themselves.

However in October, Ofcom gave the service the go-ahead.

"Whether or not YouView and its partners will harm competition in the ways alleged will depend upon how this emerging market develops and how they act, particularly in relation to providing access to content and issuing technical standards," Ofcom said.

"IPTV is still an emerging sector, and the impact of YouView on the market will not be known with any confidence for some time."