As leader of the “Brolly Brigade” as Fleet Street dubbed the Civil and Public Services Association (CPSA), Britain’s largest union for civil servants, Ken Thomas led civil servants in some fierce disputes with the Government over pay and pensions in the strike-prone 1970s and early 1980s, notably fighting a losing battle with Margaret Thatcher’s Government.

Representing the interests of more than 235,000 Whitehall workers, Thomas led the first national civil servants strike in Britain in 1981, after the Government had announced 75,000 job cuts. It lasted five months, and welded together disparate groups of civil servants as a common voice. But at the end, with the union’s funds depleted and surrender inevitable, Thomas was accused at the CPSA’s national conference of having humiliated workers by accepting a 7.5 per cent pay increase.

Only a few years earlier, when he had been deputy general secretary, members of his union had paid Thomas the accolade of a standing ovation at its annual conference for his obtaining a radical reform of Civil Service pensions, which gave pension rights to widowers and improved rights for women, who at one time had been forced to retire from the Civil Service upon marrying. This truly modern Civil Service pension scheme was introduced in 1972-73.

Within the CPSA Thomas often clashed with those on the extreme Left of the union, which made repeated attempts to unseat him before his eventual retirement in 1982.

Kenneth Rowland Thomas was born in Penarth, Glamorgan, and worked briefly as a trainee journalist for the South Wales Echo and Western Mail before joining the Civil Service in 1944. In 1955 he became assistant secretary of the CPSA, rising through the ranks to be appointed secretary general of the union in 1976. He was also a member of the TUC General Council, 1977-82.

He set out to challenge the assumption, often voiced, that Civil Service trade unions “bumbled away” in a “quiet backwater isolated from the main stream of aggressive union activity”. He asserted that Civil Service unions had always had to fight to be considered as equal to other unions, pointing out that after the First World War, when agreements were drawn up by the Government for greater employer-employee consultations with the trade unions, the Civil Service unions had been left out.

By the time he assumed the reins as secretary general of the CPSA in 1976, the Labour Government was threatening to push through a £95 million spending cut in the Civil Service, representing a loss of 26,000 jobs. He co-wrote a pamphlet with Gerry Gillman, general secretary of the Society of Civil and Public Servants, which accused the press of running a “hate campaign” to bolster the myth that civil servants were pampered. This, Thomas claimed, ignored the facts: about two-thirds of civil servants earned less than the average wage.

In 1977 there was a spate of strikes by air traffic control assistants at Heathrow, who wanted a 17 per cent pay rise that they had been awarded in June 1975, but had never received, because of government pay restraints. In the winter of 1978-79, the “Winter of Discontent” that perhaps more than anything brought down the Labour Government of James Callaghan, the CPSA, whose national executive had by that time been captured by the Left, took strike action in pursuit of wage claims of more than 20 per cent. Thomas blamed the union’s leftward lurch on the Government’s pay restraint policies, but led the CPSA vigorously during a series of strikes that hit public sector services severely. The advent of a Conservative Government under Margaret Thatcher in May 1979 changed the chemistry of such industrial disputes and the CPSA was subsequently to receive a bloody nose.

On his retirement in 1982 Thomas asked the union to commission a symphony from Daniel Jones as his leaving gift. It was the Welsh composer’s 12th and last symphony.

Thomas is survived by his wife, Nora, and three sons; a fourth predeceased him.

Kenneth Thomas, OBE, general secretary, Civil and Public Services Association, 1976-82, was born on February 7, 1927. He died on August 12, 2008, aged 81