It is in large part due to Audrey Callaghan, who has died aged 89, that her husband, James Callaghan, the then chancellor of the exchequer, remained in politics after the devaluation of sterling on November 18 1967. Were it not for the advice of his wife in the course of their long private discussions late into that night, he would have resigned from the government and would thus never have succeeded Harold Wilson as prime minister in 1976.
Callaghan was determined to leave the Treasury after the ignominy of devaluation, contrary to his repeated assurances to the City and international markets that it would not happen. Wilson persuaded him to accept a move to the Home Office, in the event swapping his ministerial responsibilities with Roy Jenkins, but according to the Callaghan family it was Audrey who deserved the credit. She was far too subtle and sophisticated a tactician to subject her husband to any direct pressure, but she did manage to convince him that, aged 55 and despite the then inauspicious circumstances, it was nevertheless possible that he might still have a future in politics.
Hers was always an understated role, unseen by the public and underestimated by politicians. It was, however, one of considerable influence, given the strength of her marriage to the man who occupied in succession all four of the principal offices of state. Their marriage was a long and fulfilled one to which Audrey, while remaining less visible than the wives of some other senior Labour politicians of the day, contributed a level-headed equability recognised throughout their family.
She liked her anonymity and hated the idea of being recognised when she moved to 10 Downing Street. Indeed, for some time after James Callaghan became prime minister, the couple briefly attempted to continue living in their modest two-bedroomed flat just over the river in Kennington in an at tempt to retain a semblance of a "normal" domestic life. It was not a feasible option, but Audrey did succeed in maintaining a low public profile, slipping in and out of Downing Street by the back entrance. Her husband once attributed the serenity of their relationship to his wife's character and admitted: "She adds an essential element of middle-class stability to my working-class insecurity."
Audrey Elizabeth Moulton was brought up in Maidstone in Kent, where her father was the director of a machine tool company, and despite the comfort of her domestic circumstances, she was imbued from childhood with the idea of public service. She joined the Labour party as a teenager and met the young James Callaghan, who had just started work as a tax officer in the area, when they were both Sunday school teachers at the same Baptist church in Maidstone. They met next at the tennis club and Audrey once said that the reason they liked each other was because they were so different. "He is very tidy and efficient," she said. "I'm not in the least like that."
She was 17 at the time and still at school. It was to be another nine years before they married, in 1938 - according to Callaghan when Audrey said it was "about time". By then she had acquired an economics degree, having studied under the late Hugh Gaitskell during his years as a lecturer in political economy before he entered politics and became the leader of the Labour party.
When she was first married, Audrey worked as a dietician in an ante-natal clinic. It helped foster her lifelong interest in the welfare of children. She said once that in the early years of their marriage her husband did not approve of women working - although he changed his mind with the passage of time - and insisted that if she did work she should keep all the money she earned herself. She used it with typical resourcefulness for a down payment on a cottage in the Isle of Wight, to which she used to take her own family on holiday. Their first child was Margaret - now Baroness Jay, the former leader of the House of Lords - born in 1940. Their second daughter, Julia, was born in 1943 and their son, Michael, in 1946.
Audrey had her own political career, which she kept typically discreet. She was an alderman on the London borough of Lewisham and on the Greater London Council. Her abiding interest was her close connection with the Great Ormond Street Hospital for Children. She chaired the board of governors from 1969 until 1982, chaired the hospital's special trustees from their inauguration in 1984 until 1990 and was a trustee involved with the hospital's famous Wishing Well Appeal for 15 years until 1999. She was a very practical woman, as well as a good organiser. She was appalled, for example, to discover how difficult it was for mothers to remain in hospital with their sick children and campaigned to ensure that this should be the common practice - as it subsequently became.
It was also thanks very largely to her efforts that legislation was introduced in 1988 to enable the Great Ormond Street Hospital to receive in perpetuity the British royalties from JM Barrie's Peter Pan, which the author had assigned to the hospital in his will, but without allowing for the expiration of copyright 50 years after his death. The unique statutory amendment was moved in the House of Lords by Lord Callaghan.
She won much praise for her stoic support for her husband throughout his political career and she was liked by his staff. During their years at 10 Downing Street, a request was received from the Ministry of Defence for the prime minister's wife to preside at the official launch and naming of a new frigate. This was approved and was going ahead until it was learned at Number 10 that the name of the new ship was to be HMS Battleaxe. Audrey was then quickly stood down by her husband's staff, who with excessive sensitivity deemed it an inappropriate function for her to attend - until, that is, she got to hear about it herself. She laughed off any possible implications and cheerfully insisted there was no reason why she should not launch the ship as expected.
Audrey was regarded by some as more leftwing than her husband. She chaired her local Labour party in Maidstone when she was a young woman and although she kept out of the picture when her husband emerged as a national figure, Labour colleagues were well aware of the degree of her understanding and influence. Tony Benn recorded in his Diaries in 1960 that Audrey had told him: "Jim was very depressed but had come back from Czechoslovakia convinced that socialism does work."
Throughout her last years, during which she became increasingly frail, she was nursed devotedly by her husband. When she first became ill, he strongly resisted any attempt to provide help in her nursing care in what their family saw as a loving demonstration of the mutual care and support the couple had provided for each other throughout their lives. In time, however, he did concede the need for her to be cared for in a retreat where he visited her daily.
In 1987, she became Lady Callaghan on Callaghan's appointment as a life peer. She is survived by her husband of 67 years - the longest-living prime minister in British history - and by their three children, 10 grandchildren and six great grandchildren.
· Lady (Audrey Elizabeth) Callaghan of Cardiff, campaigner and fundraiser, born July 28 1915; died March 15 2005
