Sir Edward Heath was "completely asexual" and allegations of child abuse against the former prime minister are “highly unlikely” to be true, according to the man who was his close aide while in office.
Lord Armstrong of Ilminster said child sex abuse allegations levelled at Sir Edward were "totally uncharacteristic" of him.
Seven police forces are investigating allegations against Sir Edward, while the police watchdog is looking at whether Wiltshire Police failed to follow-up abuse claims against the late PM in the 1990s.
Lord Armstrong, who as Robert Armstrong was the Conservative leader's principal private secretary during his time as prime minister from 1970 to 1974, told the BBC he "never felt a whiff of sexuality about Ted Heath, whether it was in relation to women, men or children".
He said: "I knew him for 35 years, I worked very closely with him while he was prime minister and we remained friends for the rest of his life.
"You usually detect some sense of sexuality when you are friends or work closely with them. I think he was completely asexual. There are some people like that and I think he was one of them."
The claims were unlikely because Sir Edward was under the guard of Scotland Yard protection officers when at home and did not drive, Lord Armstrong added.
"It just seems to me highly unlikely that he could have escaped all that to do the kind of thing that is described," he said.
His comments come after a former brothel keeper claimed she had arranged male escorts for the former premier.
Myra Ling-Ling Forde, 67, said Sir Edward was a "shy gay man" but not a paedophile.
Sir Edward died at home in Salisbury at 89 in July 2005.
Lord Armstrong, who became cabient secretary under Margaret Thatcher, added that the police's decision to speak to reporters outside Heath's house as "disgraceful" and said the investigation should have been carried out in private.