Rupert Hughes: Senior civil servant whose determination was vital in bringing the Children Act 1989 to the statute books

That he was courteous and never spoke ill of anybody must have eased the often politically charged atmosphere within which civil servants work

Hughes: with typical scrupulousness, he set up 22 committees to test implementation of the new law

Self-effacement and an apparent shyness masked the steely determination and persistence which enabled the senior civil servant Rupert Hughes to bring to the statue book the Children Act 1989, one of the most influential, respected and long-lasting pieces of postwar legislation.

It came in the wake of more than a decade of child deaths and resultant inquiries that caused public and political dissatisfaction with child protection, family capacity and legal remedies. This grew increased with the Cleveland scandal of 1987. The Act drew together, rationalised and codified the varied and confusing private and public law which governed the welfare of children – the courts, protection, adoption and fostering, family support, children homes, and care orders, among them.

But it also established what has become the absolute criterion to determine children's welfare: the best interests of the child. This concept became so culturally embedded that it is now used in matters far wider than the Act's remit. The Act, and accompanying statement of principles and guidance, created a legislative framework within which there was an acknowledgment of the potential for professional discretion.

Three remarkable things enabled Hughes to create a unique legacy. He was assistant secretary, children's services division, Department of Health and Social Security. First, the Act was passed when Margaret Thatcher's Conservative government was instinctively antagonistic to state intervention. Second, Hughes effected an unusual achievement in those divisive times: whole-hearted cross-party agreement (there was one division in its progress through both Houses, and that was on a technical point). Third, with the actively benevolent support of Lord Mackay of Clashfern, the Lord Chancellor, and a liberal Health Secretary, Kenneth Clarke, Hughes also had a fairly free hand within his department.

But he had not only to contend with politicians and other government departments. He also had to engage with, and ultimately command the respect of, a whole range of outside interests, from the police to charities – seeking consensus, and, if necessary, soothing egos and unruffling feathers.

In 1984 a Commons social services select committee had criticised the jumbled state of the law and made 200 recommendations. This led to an inter-departmental committee, which Hughes chaired. Here he believed strongly that policy and legislation should be informed by research, by no means common practice, then or now. The committee reported in 1985 after 14 months; the 74-clause bill was introduced in November 1988, becoming law a year later, and was implemented in 1991.

It was typical of Hughes' scrupulousness and commitment to impact, as well as design, that he set up 22 projects to test implementation of the legislation, as well as instituting nationally organised training sessions to equip lawyers, social workers and judges to ensure the Act's efficient operation.

Baroness Hale, now deputy president of the Supreme Court, and then professor of law, Manchester University, and a member of the Law Commission, has been described as the "mother" of the Act to Rupert's "father". She described their joint endeavour as "a labour of love on both our parts".

Hughes was one of two sons of Rev CRG Hughes (and the grandson of a clergyman) and was brought up in Portsmouth. The family moved around as their father moved parishes, including on the Isle of Wight, where he held several livings. Rupert and his brother Michael were educated at Lancing College, Sussex, and Rupert gained a scholarship to read Classics at Worcester College, Oxford. He graduated in 1956 with a First.

In the light of this semi-peripatetic childhood, and not marrying and having children himself, it is even more outstanding that one fundamental tenet of the Act is that, where possible, children be brought up by their own families.

He joined the Ministry of Agriculture and Fisheries straight from university, later moving to the Cabinet Office. Then in 1984 he went to what was then the DHSS.

A friend and former colleague described him as "not a 'yes' man but a 'yes, but…' man". His acute intelligence and independent mind, combined with his willingness to listen, gave him an ability to make informed decisions, and along with a deep commitment to his work, made him an example of the best kind civil servant. That he was courteous and never spoke ill of anybody, personally or professionally, must have eased the often politically charged atmosphere within which civil servants work.

In retirement after 1995 he lectured in Australia, chaired the Michael Sieff Foundation for three years and became one of the first fellows of the Centre for Social Policy, at Dartington, Devon, where he was chair for three years.

Tall and angular, he was remarkably fit enough to be climbing in Scotland at 80 (mountain climbing was a hobby he followed in the UK, Europe and elsewhere). He was affable, private, yet companionable; someone who liked good wine, valued friendship, loved the Reform Club and enjoyed classical music, especially opera. He had a sceptical intelligence that would test a companion's statement, with an impish look, with the question: "Is that really so?" or "Do you really mean that?"

These were, no doubt, the kind of questions which he asked in the discussions which led to the drafting of what became an exemplary piece of legislation. But that was all to one end – to promote the welfare of children.

Hughes remained a questioning but convinced Anglican and his funeral took place at his parish church, the 18th century St Michael's, Paddington Green. He is survived by his partner, Priscilla Campbell Allen.

Rupert Paul Sylvester Hughes, civil servant: born Hampshire 5 January 1935; CBE; died London 15 August 2015.