A trusted visitor to one of Britain's biggest picture libraries has been found guilty of stealing thousands of historic photographs.
Adrian Rigelsford said he found some photographs in a skip
Adrian Rigelsford, 34, an author from Huntingdon, Cambridgeshire, had denied one count of theft from library owners, Kensington-based Associated Newspapers.
At Blackfriars Crown Court on Friday he was found guilty of stealing in excess of 10,000 "unique and priceless" shots.
The theft was discovered when some of the photographs were spotted on sale.
The court was told an inquiry began in 2002 after some of the library's collection were seen in two London shops.
The photos were said to include turn-of-the-century shots of the Royal family and the Yalta Conference - the 1945 meeting of Churchill, Roosevelt and Stalin to discuss post-conflict Europe.
Penny Rector, prosecuting, said between 1994 to 2002 Rigelsford, a Dr Who expert, stole about 56,000 prints and sold them on, making an estimated £75,000.
Photos of the 1945 Yalta Conference were stolen
Rigelsford denied he stole the photographs, insisting he had taken possession of them innocently.
He said some he took from a skip outside the library - a security guard told him it was "okay" to take them - and others from a sack being thrown out by a cleaner.
He had been visiting the library for 10 years and was trusted to collect and return photos by himself while he carried out research.
The author, who has ghosted biographies on actors Peter Sellers and Brian Blessed, was warned he faces jail when he is sentenced in four weeks time.