ITV today confirmed it has struck a deal to launch high-definition versions of its digital channels on Sky.

The broadcaster announced that HD versions of ITV2, ITV3 and ITV4 will launch as part of the Sky+HD subscription package of channels this autumn.

It is the first-step in a five-year "Transformation Plan" to reduce ITV's reliance on advertising revenue and broaden its income streams.

ITV's chief executive, Adam Crozier, said: "For the past decade ITV has not faced up to the challenges presented by the rise of internet-based platforms, the continuing growth of pay-TV and subscription services and the globalisation of content.

"Our priority for the next 18 months is to make ITV a creatively dynamic and fit-for-purpose organisation while maintaining strict financial controls. Over time we expect to move to a position whereby half of ITV's revenue base will be derived from non-television advertising sources and today we are announcing our move into pay television with the agreement to make HD versions of ITV 2, 3 and 4 pay channels on Sky."

The move was announced as ITV revealed improved financial performance for the six months to 30 June.

A boost in advertising revenue from the World Cup helped it return to the black with pre-tax profits of £97m - a notable improvement on its £105m losses during the same period last year.

ITV said its net advertising revenues rose 18% in the first half of 2010, compared with a rise of 15% for the wider market.

It expects growth of 15% in the current quarter but warned that it was "cautious" about the outlook for the fourth quarter and into 2011 because of economic uncertainty.