LONDON (AFP) - Prince William has admitted there is "no greater feeling" than saving someone's life while working as a search and rescue helicopter pilot, in an interview released on Thursday.

The second in line to the British throne, who has been working as a Royal Air Force pilot in Wales since Jan 2010, said it was stressful but nothing compared to the satisfaction of bringing someone home safe.

"There's no greater feeling than when you've actually done some good and saved someone's life," Prince William told a BBC TV programme on the emergency service, which is due to be broadcast next week.

"I don't think there's any greater calling in life... to be able to see a son or daughter's face when you bring their mother or father back from the edge of death - it's quite powerful."

Prince William, 30, began his training as a search and rescue pilot in Jan 2009, a job which involves flying in dangerous weather conditions to rescue stranded climbers or seamen.

Flight Lieutenant Wales, as he is formally known in the military, qualified as a co-pilot a year later and was promoted to command the crew of four last year.

But his future is uncertain following the privatisation of the search and rescue service, which was announced this week.

Prince William is known to have expressed his concerns about the privatisation plans to Prime Minister David Cameron when they were first mooted.

The prince's tour at RAF Valley was already due to end this year but he has yet to publicly announce his next move.

The prince and his wife, Catherine, are expecting their first child in July. They have a home in Wales as well as in London, enabling them to mix military life with public engagements.

In one rescue followed by the BBC programme, the prince captains an aircraft called to save a boy who has fallen off an old railway bridge and onto rocks.

He described how, when an emergency call came in, he immediately started to plan out what he should do.

"As captain, you're trying to play out the entire rescue, the transit to the rescue and back again in your mind, and pick up any circumstances or problems you can foresee, and try and fix them on the ground before you get airborne," Prince William said.

The military will end its 70-year-old involvement in the search and rescue service in 2016, when Texas-based Bristow Helicopters will take over in a deal worth 1.6 billion pounds (S$3 billion).