Sir Denis Thatcher used his final interview to denounce John Major, speak warmly of his marriage and to reveal he was unaware of the Falkland Islands' location when they were invaded.
Baroness Thatcher said she could not have done without Sir Denis
Talking to daughter Carol a few months before his death in June, he said his wife's successor at Number 10 was a "ghastly" prime minister.
And he put the blame for the current state of the Tories firmly at Mr Major's feet.
In the interview, to be screened on Sunday, the 88-year old also talked of the treachery that brought his wife down.
He said he knew that 1990 was the year for Margaret Thatcher to quit and had told her so but instead she hung on and was effectively forced out later that year.
"I think she was ready to go. Not to be kicked out. To say, 'I've had enough,
I want to hand over'. And go at the top. Undefeated."
He also says he saw her downfall coming when she only beat of a challenge for the leadership narrowly but he held his tongue.
Asked why he said: "She might have thought I
was undermining her position. She might have thought I had not the ability to
stand firm. I don't know. But I didn't. But I could see it coming."
Sir Denis also showed a mischievous side remarking that when he met the wives of US presidents he "wasn't trying to get off with them".
On the treatment of his wife by her senior ministers he said it was "appalling".
"[People] said how could they do it? And it would have been a very, very good
thing if the next election after Margaret went we had lost.
"If Major had lost, we wouldn't have had the disaster we've got now.
"He was a ghastly prime minister, more people deserted our party and we have never recovered.
"The whole of the situation of the Conservative Party today springs from that night when they dismissed the best prime minister the country had had since Churchill."
Politics was not, said Sir Denis, a way of life that attracted him.
He said that was in no small part because of the "dashing about from meeting and meetings, meeting and greeting, canvassing".
And he said he had to be careful to avoid tabloids mocking him.
"Don't give them a chance to either make fun or be rude," he said.
"And certainly don't get caught by the press having too much to drink. You
had to be a bit cunning."
Sir Denis also described the day that it emerged Argentina had invaded the Falklands.
"When I arrived back into Downing Street, I won't say it was panic stations, but everybody was running around.
"I wasn't absolutely too sure where the Falklands was, and I didn't want to
make a bloody fool of myself."
But when asked by his daughter about his long marriage to the UK's first woman prime minister he appears momentarily flummoxed.
"In cricket terms, you've bowled me a googly, haven't you?
"I don't know, love, I really don't. What it meant to me: a happy life, of
course, companionship, of course. A common objective, I think."
The interview is a key part of a film about Sir Denis' life due to be broadcast on Channel 4 on Sunday 3 August.