Nigel Fox Bassett was the senior partner at Clifford Chance, the London- based law firm that has grown into one of the world’s largest commercial practices, from 1990 to 1993, and he was closely involved in the 1987 merger that created it.

On retirement, Fox Bassett was appointed to the Building Societies Commission, the mortgage lenders’ regulatory authority. During his eight-year term at the BSC most of Britain’s biggest building societies — including the Halifax, the Woolwich, Alliance and Leicester and Northern Rock — swapped mutual ownership by customers for life as Stock Exchange-listed banks.

Fox Bassett was born in 1929, attended Taunton School and Trinity College, Cambridge, where he read history and law. He qualified as a solicitor in 1956 and in 1960, at 31, was made a partner of Coward Chance, a forerunner firm of Clifford Chance.

In the early 1960s expertise at the firm was less specialised than it is now and Fox Bassett won respect for his work in the commercial and financial fields of law. Federal Mogul, the US engineering company that was expanding overseas, was a client, as was Pioneer Concrete of Australia and Cubazucar, the Cuban state marketing organisation. In 1971 Fox Bassett acted for the Government of Argentina in a boundary dispute with Chile centred on the Beagle Channel near Tierra del Fuego. His expertise was sought by overseas banks wishing to establish branches in the City of London.

His practice included work resulting from the 1986 Financial Services Act, especially where it applied to the running of futures and options exchanges.

Internationalisation featured strongly in Fox Basset’s long career. At his instigation Coward Chance opened its first overseas office, in Brussels, in 1973. It was followed by moves into Dubai, Sharjah, Hong Kong and Singapore. Legal professionals are often cautious, and some partners at Coward Chance often expressed nervousness about expansion, fearing it would dilute the strength of established practices in London, and elsewhere. Had it not been for the determination of Fox Bassett, the expansion would have been delayed and might not have taken place at all.

Fox Bassett was part of the team at Coward Chance that orchestrated the 1987 merger with Clifford-Turner, which catapulted the newly merged firm to the top of the list of biggest law practices. The network of foreign offices proved a critical element in the negotiations with Clifford-Turner. They were important bases from which the merged firm grew.

At the outset Clifford Chance had joint senior partners: Tom Johnson-Gilbert from Coward Chance and Sir Max Williams from Clifford-Turner. In 1990, Fox Bassett was elected to the post outright.

As with most mergers, the integration was occasionally fraught. In this case, established lawyers with strong ideas and entrenched habits became obliged to embrace change. Few partners in either firm had many dealings with those of the other firm, reflecting the fact that the two practices were quite different.

Following an initial period of familiarisation after 1987, contemporaries remember Fox Bassett’s tenure as senior partner as make-or-break time. Jeremy Carver, a longstanding colleague of Fox Bassett at Coward Chance and then Clifford Chance, said: “The period of 1990-1993 was crucial in ensuring that the merger worked . . . without Nigel’s rock-like dependability as senior partner, it might have failed.”

Fox Bassett was succeeded by Keith Clark in 1993. He served with distinction as chairman of the executive committee of the British Institute for International and Comparative Law, as honorary treasurer of the British branch of the International Law Association, and in the City of London Law Society. In 1998 he joined the board of London First, the business lobby group dedicated to raising the profile of the capital abroad.

He married his wife, Anne, in 1961 and he is survived by her, a son and a daughter.

Nigel Fox Bassett, senior partner of Clifford Chance, 1990-93, was born on November 1, 1929. He died, after suffering an aneurism, on October 26, 2008, aged 78