Former Thatcher PR guru Lord Bell told a vile joke about the Germanwings plane crash during an interview on BBC Radio 5Live today.
Listeners were disgusted to hear the Tory peer tell the sick 'knock knock' joke live on air - despite saying he'd get "shot" for doing so.
Baron Timothy Bell - one of the masterminds of the Tories' 'Labour isn't Working' poster campaign in the 1970s - was talking about using negativity and humour in election campaigns.
He told host Adrian Chiles: "Most humour is at the expense of somebody".
"There's a terrible knock knock joke going around at the moment," he said, "which I'm not going to do on air because I'll probably get shot."
But he then proceeded to laugh and tell the joke anyway, saying: "Knock Knock. Who's there? The pilot."
Shocked Adrian Chiles responded, saying: "But that's an awful one, you wouldn't get into anything like that in political advertising."
Bell suggested people singing "Ding Dong the Witch is Dead" following the death of Lady Thatcher was similarly distasteful.
Chiles said: "Well that's true, but that was generally held to be rather unpleasant and not very British."
Listeners took to social media to express their outrage at Bell's comments.
At the end of the show, Adrian Chiles apologised "to any listeners that were offended by Lord Bell's "joke" earlier."
Both Lord Bell and the Conservative party were approached for comment, but neither had responded at the time of publication.
On March 24 Lufthansa-owned Germanwings Airbus crashed in the French Alps. All 150 aboard died.
The plane's pilot had been locked out of the cockpit, and was reportedly heard knocking on the door to get back in on the flight recorder. It's thought the plane was deliberately crashed by 27-year-old co-pilot Andreas Lubitz.
Bell was nominated to become a life peer in by Lady Thatcher, and made Baron Bell of Belgravia in 1990.