LONDON - Former British prime minister Edward Heath would have been questioned over claims that he sexually assaulted five boys if he was still alive, police announced Thursday.

Heath, who was Britain's premier between 1970 and 1974, is alleged to have raped an 11-year-old boy during a paid sexual encounter, officers revealed following a mammoth two-year investigation.

Heath, who died in 2005 aged 89, would have been interviewed under caution over seven allegations dating between 1961 and 1992, relating to five boys and two adult men.

"Sir Edward Heath was an extremely prominent, influential and high-profile person who was arguably one of the most powerful people in the world," Wiltshire police chief constable Mike Veale said, announcing the investigation's findings.

"The allegations against him were of the utmost seriousness and from a significant number of people."

The £1.5 million ($2 million, 1.7 million euro) probe was triggered in 2015 after Heath was named as a suspect in an investigation into so-called historical child sex abuse.

Of the 42 allegations made against Heath, seven were sufficiently credible to justify the police questioning him under caution.

Those allegations including the rape and indecent assault of an 11-year-old boy during a paid sexual encounter in 1961 and the indecent assault of a 10-year-old boy in 1962.

In addition, he allegedly indecently assaulted two boys aged 15 in the 1960s, and one aged between 12 and 14 in the early 1990s, as well as two adult males in 1976 and between 1990 and 1992.

Six people named Heath in accusations of satanic or ritual abuse, but police found no corroborative evidence.