Exclusive: Bob Hawke’s widow, Blanche d’Alpuget, has unveiled a shocking plan she once entertained: the murder of her husband before his rise to become prime minister.

d’Alpuget, an accomplished author, had contemplated spending her prison time writing after committing the act. She ultimately abandoned the idea, fearing the impact it would have on her six-year-old son, Louis, growing up with a mother guilty of murder.

Her intentions, albeit fleeting, were genuine.

“No, no, from the front. I could never stab someone in the back.”

“No, no, from the front. I don’t believe in stabbing people in the back.

“I don’t know that I entertained the idea longer than 24 hours.

“It was really out of consideration for my son that I dropped the whole lot.”

Hawke, drunk, had proposed to Blanche, who then left her husband.

Hawke months later reneged on the promise and stayed with his wife Hazel because of the political damage a separation would cause.

He went on to be elected PM in March 1983 and is widely regarded as one of Australia’s best.

“He had asked me to marry him and then reneged. Very sensibly, I might say,” she said.

“Thank God he did, for everybody’s sake, especially Australia’s. And I was terribly hurt. That was all.

“I think I thought of suicide and then I thought, no, it would be better that he died rather than I died.

“I mean, this is love, you know. It can be turmoil.”

Blanche explained her plans, speaking on the podcast Neil Mitchell Asks Why, about the release of her biography Fridays With Blanche.

Hawke eventually did leave Hazel almost 20 years later and married Blanche in July 1995.

In the meantime, they continued a clandestine affair, meeting at the prime ministerial residence and even on his official aircraft.

Hazel Hawke was an engaging and warm person with a superb sense of humour and an infectious laugh.

She was greatly admired by the public for her down-to-earth approach and for tolerating Bob’s infidelity and drunkenness through 38 years of marriage.

When the marriage ended, Blanche became arguably and unfairly the most hated woman in Australia.

“Although Bob had been an absolute philanderer and had hundreds of women during his time married to Hazel, I was the one blamed for the breakup of their marriage,” she said.

Despite her initial murderous intent, Blanche came to see that she would have changed history by killing him, and indeed by not killing him.

She has no illusions about why Hawke reneged on his marriage proposal before he was PM, and says his decision to stay with Hazel was the right one.

“I think politics was a very big part of it,” she said.

“Probably the main part of it, actually.

“It was good for Australia. He was very good for Australia.

“It was the tension between love and duty And he obeyed the call to duty.

“Which is how he saw it and how I see it.”

In an unfashionably frank interview, and in the book, Blanche talks freely about:

She has no doubt he was an alcoholic.

“As with all alcoholics, he had an on button and no off button,” she said.

“He could drink and drink and drink but he couldn’t stop drinking once he started.

“He asked me to be the parole officer to watch his drinking, which I really hated.”

And finally, on the murder that wasn’t:

MITCHELL: Did you ever tell Bob that you had planned to kill him?

D’ALPULGET: Oh yes, I think I did. We laughed. We laughed. He’d laugh and say, “If you decided you were going to do it, I wouldn’t want to be in the way.”

Neil Mitchell is a broadcaster and journalist who hosts the Nine podcast Neil Mitchell Asks Why?

Fridays with Blanche was written by Derek Rielly. It is published by Allen and Unwin.