As the private differences broke out into public, Mrs Cook, a consultant haematologist in Edinburgh, launched a vicious and highly personal attack on her ex-husband in her autobiography detailing their marriage.
In the book, she paints a picture of an unhappy and unstable man who was cruel to her and felt "glum and disillusioned" by Tony Blair's changes to the Labour Party. The Foreign Secretary believes he has "sold his soul to the devil" and that "Tony Blair had sold the Labour Party's soul to the devil", she claims.
During the 1987 general election campaign, Mrs Cook says her husband was "clearly drinking heavily and his mood was one of wary depression." On one occasion, Mrs Cook claims in A Slight and Delicate Creature, she found him "flat out on the dining room floor with a brandy bottle".
The Cooks divorced after the Foreign Secretary admitted having an affair with Gaynor Regan, his secretary, whom he has since married. However, Mrs Cook says this was not an isolated incident of infidelity.
She describes how, as they sat drinking one evening, "with no hint of regret or apology but rather like an indulged naughty schoolboy, he related the catalogue of previous affairs. He named five women that I can recall but apart from being drunk I was soon sated with information and may not remember all the confessions."
Mr Cook's friends hit back at the allegations, denying that he had ever had a drink problem. "Her claim that he had a drink problem is not true," one ally said. "Nobody who knows Robin and knows how hard he works is going to believe this. This is a man who has been criticised for not spending enough time in the bar drinking."
Harriet Harman, who was Mr Cook's deputy in the health brief in the run up to the 1987 election said she was "astonished" by the allegation. "It never crossed my mind that anyone could even have a suspicion that Robin could possibly have had a drink problem," she said.
The friend also dismissed the claim that Mr Cook had accused Tony Blair of selling the Labour Party's soul "to the devil". He said: "This is in her head. Robin has never said any such thing and he doesn't believe any such thing. This is total invention."
A Foreign Office spokesman said: "Robin Cook will not be responding to his ex-wife's account of their marriage nor has he authorised anyone to comment on their marriage. The Foreign Secretary is getting on with his work."
Pressure on Mr Cook will increase this week when Sir David Gore-Booth, former ambassador to Delhi, is expected to launch an attack on his leadership of the Foreign Office in evidence to the Commons Public Administration Committee.Reuse content