Sinclair only stopped working for the broadcaster in 2005, aged 82, when his firm was still supplying 92 vehicles.
A glowing 2005 profile on the BBC website, still online tonight, was headlined: “A driving force behind BBC shows.”
Sinclair groomed boys by paying them for odd jobs. He would then offer them wine and force himself on them at his flat in Stanmore, North West London.
He was jailed for six months in June 1961 for indecent assaults on two boys.
In March 1966, he got five years for buggery and indecent assault on one boy and a second indecent assault on a lad aged 12.
And in May 1971, he was convicted of buggery and sexual assault of four boys aged 13 to 14.
He previously admitted possessing a Beretta pistol without a firearms certificate.
The trial heard he showed the gun to at least one victim, saying they had “better get undressed or he would shoot”.
Speaking at his home in Godalming, Surrey, today, Sinclair told the Sunday People: “I was contracted to the BBC via my company, I was never a direct employee so there was never any reason for them to check about my convictions.
"But that was a very different chapter in my life.
"The only reason I’m being dragged into this now is because of Jimmy Savile.”
A BBC spokesman said: “The BBC has no dealings with Niven James Sinclair today.
"We are not aware of any complaint having been made to the BBC about him. We have robust child safety procedures.”
They could not comment on the processes of 40 years ago as to why Sinclair was contracted in 1977 following his convictions.