LONDON (Reuters) - British Formula One great Stirling Moss is recovering in hospital in Singapore after the 87-year-old was admitted in December with a serious chest infection, his website said on Saturday.

Widely regarded as the greatest grand prix driver never to win the world championship, Moss was a team mate at Mercedes to the great Argentine five-times world champion Juan Manuel Fangio.

He finished runner-up four years in a row from 1955 and remains the most successful driver not to take the title, with 16 race victories. He was also the first British driver to win his home grand prix, in 1955.

The website said Moss had been admitted to hospital on Dec. 22.

"Because of the severity of the infection it resulted in some complications and his recovery has not been as speedy as was expected or wished," it said.

"However, his condition continues to improve and his doctors now consider him to be stable.

"In himself, Sir Stirling is in good spirits and only upset about having missed his Christmas cruise with friends."

Moss announced his retirement from motor racing only in 2011, at the age of 81. He had been due to race his own restored 1961 Porsche RS61 in a Legends race at Le Mans that June.

He ended his professional career after a bad accident at Goodwood in 1962 but had continued racing historic cars for his own pleasure.

In March 2010, he survived a three-storey plunge down a lift shaft at his London home, breaking both ankles and four bones in his feet. He was back behind the wheel again by July.

(Reporting by Alan Baldwin, editing by Greg Stutchbury)