It's alleged a Conservative minister in the 1960s, who was also a Devon MP, sold information about his colleagues and Parliament to communist spies.
It's reported Czech Security Service files reveal Raymond Mawby, who died in 1990, was in its pay for a decade.
Watch the full report from Bob Cruwys:
It's said he supplied spies with a floorplan of the prime minister's Commons office, lists of parliamentary committees, information about colleagues and a supposedly confidential parliamentary investigation into a Conservative peer.
Mr Mawby, who served as MP for Totnes from 1955 until he was deselected in 1983, was a gambler and began accepting "loans" while playing roulette and other games, the files claim.
He later went on to accept payments, usually for £100 a time, for information and was given the codename Laval.
"Mawby has also promised to carry out tasks such as asking questions in Parliament according to our needs," documents written by a Czech handler in 1962 show.
Mr Mawby became assistant postmaster general and a junior minister in 1963.
Today in Parliament, the current MP for Totnes, Sarah Wollaston, called for a full inquiry.