Child sex allegations involving Sir Edward Heath are at the centre of a police corruption investigation.
Watchdogs named the late Prime Minister as they announced Wiltshire Police is being probed over its response to an alleged abuse claim made in the 1990s.
The force appealed for potential victims to come forward.
Sir Edward, who was PM for four years in the 1970s, is the highest-profile figure to be embroiled in historic abuse allegations against prominent figures.
The Independent Police Complaints Commission (IPCC) said it is to investigate "allegations concerning Wiltshire Police's handling of an alleged claim of child sexual abuse made in the 1990s".
A spokesman said: "It is alleged that a criminal prosecution was not pursued, when a person threatened to expose that Sir Edward Heath may have been involved in offences concerning children.
"In addition to this allegation, the IPCC will examine whether Wiltshire Police subsequently took any steps to investigate these claims."
The allegations were referred to the watchdog following allegations made by a retired senior officer.
A spokesman for Wiltshire Police said: "Following the announcement today regarding an independent investigation by the IPCC into allegations concerning how Wiltshire Police handled an alleged claim of child sex abuse made in the 1990's, we are carrying out enquiries to identify if there are any witnesses or victims who support the allegations of child sex abuse.
He confirmed Sir Edward has been "named in relation to offences concerning children", adding: "He lived in Salisbury for many years and we would like to hear from anyone who has any relevant information that may assist us in our inquiries or anyone who believes they may have been a victim."
The force said it takes all reports of child abuse "very seriously".
The spokesman added: "If there is evidence of offences having been committed we will ensure that , if possible, those responsible are held to account through a thorough and detailed investigation. This includes any other parties who are identified as having been involved in child sex abuse.
"Some people may never have spoken out about the abuse they have suffered but we would urge them to please contact us and to not suffer in silence."
Wiltshire Police and Crime Commissioner Angus Macpherson appealed to victims or anyone with information to have the courage to come forward.
He said: "It is important that the IPCC investigation is given full co-operation. I will be watching closely to see if any evidence of corruption or poor practice is uncovered.
Sir Edward, who led the Conservative government between 1970 and 1974, never married and was famously reticent about his private life.
One biographer concluded that he may have been a latent or repressed homosexual while another thought he was "pretty well sexless".
Away from politics he was noted for his enthusiasm for sailing and classical music.
Sir Edward died at home in Salisbury aged 89 in July 2005.