Dr Cook, who was married to Mr Cook for 28 years before they split in the late 1990s, and has two adult sons by her former husband, said that one of his best attributes was that he was an "exemplary father" who was "very close" to his children.
"It's a terrible shock and a terrible tragedy. He was so young and had so much to offer. In these troubled political times he was a heavyweight on the right side, not least on the war in Iraq," Dr Cook, a retired NHS consultant, said.
She was given news of Mr Cook's death after their sons, Peter and Christopher, had been informed. The two were "gutted", she said, and were yesterday travelling to Scotland from their respective homes in Bristol and London.
The couple's marriage came to an end in August 1997, when Mr Cook was forced to admit to his wife that he was having an affair with his then secretary, Gaynor Regan, whom he went on to marry.
Dr Cook later recounted in her memoirs how Mr Cook, then the foreign secretary, told her of the affair in the VIP lounge at Heathrow airport after receiving a phone call from Alastair Campbell, informing him that a tabloid newspaper was to print the story.
Public acrimony over the book continued when, in 2002, Mr Cook spoke of the happiness his new marriage had bought him, praising his new wife, Gaynor, 11 years his junior, for teaching him "emotional intelligence". Dr Cook responded by remarking that her former husband was "not renowned for his tact".
The new Mrs Cook proved to be a devoted wife, often accompanying her husband to political events. In contrast to Dr Cook, she has remained silent about her relationship.
However, in recent times the former consultant haematologist at St John's Hospital in Livingston, near Edinburgh, has appeared happier, leaving the NHS to work as a writer.
Dr Cook said yesterday that she hoped to attend the funeral of her former husband, but added: "Obviously, I will take Gaynor's wishes into account".
Dr Cook has written a second book, Lords of Creation - The Demented World of Men in Power, and, reflecting on her former husband's career, observed that although he was "brilliant" in opposition, in particular during his savage dissemination of the Scott report, an inquiry into the arms-to- Iraq affair, she did not find him suited to power. "He was an absolute brilliant, gold standard, in opposition. He just knew how to do the background work and was a brilliant orator," she said.
"The Scott report was his top point in his career and he totally confounded the government of the day. I don't think he handled power well because of the necessary conflicts and deviations with his own essential personality and ethical style." Describing the impact his decision to resign from government had, she continued: "His whole life had been geared to getting into government and he was giving it up in a truly moral stand which was typical of him."
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