Investigative reporter who hunted down spies

Chapman Pincher, who has died aged 100, was one of the most successful British investigative reporters of his generation.

In more than 30 years with the Daily Express, he uncovered story after story about espionage and the intelligence network. His secret contacts – many of them in extremely high places – were the envy of his rivals in Fleet Street.

Pincher believed that Harold Wilson and other members of the Labour Party, like Tom Driberg MP, were Soviet agents. He also believed that Roger Hollis, who died in 1973 and who was head of MI5 from 1956 to 1965, was a Soviet mole. He took some 600 pages in his book Too Secret Too Long (1984) to try to demonstrate this, ploughing through the intriguing cases of a litany of British agents, including Guy Burgess, Donald Maclean, Kim Philby, Anthony Blunt, George Blake, Gordon Lonsdale and others. Experts said the evidence about Hollis was "suggestive", but that it fell short of proof.

Peter Chapman Pincher was born in India and educated at Darlington Grammar School and King's College, London. He began his professional life as a scientist. He joined the Daily Express in 1946 and was to dominate Fleet Street for 30 years. He was revered by colleagues and regarded with awe, and sometimes trepidation, by ministers and officials.

But not everyone had such a high opinion of him. Historian EP Thompson once described him as “a kind of official urinal in which, side by side, high officials of MI5 and MI6, sea lords, permanent under-secretaries, nuclear scientists . . . stand patiently leaking in the public interest”.

He is survived by his third wife, Billee, and children Patricia and Michael from a previous marriage.