Sky has reported operating profit of £601m for the six months to the 31 December - with more than 4m subscribers now signed up to HD TV.

The broadcaster generated revenues of £3.36bn for the second half of 2011, up by 6% on the same period the previous year. Operating profit grew 16% from £520m in 2H10.

Sky now generates a record average of £544 per year from its 10.4m customers, up from £536 over the same period in 2010. The number of HD customers has grown by 138,000 from 3.4m homes while the number of net household additions grew by 100,000.

Triple play subscribers, who buy TV, broadband and telephony from Sky was up 26% year-on-year, to 3m while churn remains flat at 9.6%.

Sky will also launch its outdoor wifi service in April, which will enable Sky Broadband Unlimited subscribers to access the internet for free via 10,000 hotspots.

Following its injection of funds into entertainment content, Sky claimed viewing of these channels in Sky homes grew by 21% year-on-year, with further investment planned.

Total programming costs were up 5% to £1.1bn over the six month period, with entertainment investment accounting for £37m of the increase while sports and movies spend remained flat.    

Sky’s chief executive Jeremy Darroch [pictured] said the business was braced for a tough year ahead.

“No consumer business can be immune to these conditions and we will manage any short-term headwinds as they emerge. Staying focused on the long-term opportunity, we’ve got a strong set of plans to keep delivering for customers and shareholders,” he said.

“This will be an outstanding year on screen, including more original British productions and a new channel dedicated to Formula 1, and we have exciting products in the pipeline that will create more ways to access our content and more reasons to join and stay with us.”

This story was first published by Broadcast.