ROWING legend Sir Matthew Pinsent has been in Purbeck uncovering his family history for BBC 1 show Who Do You Think You Are?

The four-times Olympic gold medallist, whose parents live in North Dorset village Child Okeford, filmed the show at the Tank Museum, Bovington. It will be broadcast tomorrow.

Matthew, who turned 37 this month, uncovered a tragic tale about one of his ancestors while searching the museum's Archive and Reference Library.

He knew that his father's family was greatly affected by the First World War - two of his grandfather's brothers were killed.

His research also uncovered the tragic death of his grandmother Kathleen's only brother, George Macpherson, who is recorded as having committed suicide.

Nik Wyness, spokesman for the museum, said after learning George was in the Tank Corps, Matthew and a film crew headed to Bovington to trawl through the archives.

He said: "They quickly discovered from our documents that George was a tank commander during the First World War, and that he actually took part in the very first tank attack in history - which took place during the battle of the Somme at a place called Flers in September 1916.

"What they discovered was both incredible and moving."

George was commanding one of the tanks. Despite their lack of experience the crews were expected to breach heavily fortified German lines. Sadly they failed.

George's tank broke down and had to turn back. When it finally returned to the fight, the German fire was so heavy it was forced to retire yet again.

In the programme, military historian Trevor Pigeon explains to Matthew that after the failed assault, George walked away from his crippled tank, took out his pistol and shot himself, unable to bear the feeling of failure.

Sportsman turned broadcaster Matthew said: "While I was growing up family history never interested me. That always frustrated my parents - that I didn't care more. My defence is that I was busy training to win gold medals.

"Since becoming a father, I feel that it's something I want to know more about so I can pass it on."

The programme also sees Matthew, father to twins with wife Dee, discover a link to Katherine Howard, the fifth wife of Henry VIII, among a number of characters from history.