An inquiry is to take place into claims evidence was altered during the police investigation into former Liberal Party leader Jeremy Thorpe in the 1970s, the BBC’s Today programme has learned.
The politician, who died aged 85 in 2014, was acquitted of conspiracy to murder the model Norman Scott in 1979.
An allegation has been made that a witness statement was changed during the original investigation.
Avon and Somerset Police has asked another force to carry out the inquiry.
The police watchdog, The Independent Police Complaints Commission, has been informed.
Mr Thorpe won the North Devon seat for the Liberals in 1959 with his energetic campaigning, and inspiring performances as a public speaker.
He went on to serve as the party’s treasurer before being elected leader in 1967, promising to turn the party into a radical pioneering force.
But his political career ended when his life became engulfed in scandal.
He was charged by Avon and Somerset Constabulary with conspiracy and incitement to murder.