David Tench: Solicitor who championed consumer rights and helped push through crucial legislation

David Tench was an indefatigable champion of consumer rights who contributed to the education and protection of the general public through his tireless lobbying and legislative work. Described by Esther Rantzen as "the consumers' legal guardian angel", he was responsible for an impressive array of legislation, including the 1977 Unfair Contract Terms Act and the 1987 Consumer Protection Act.

Tench was an energetic, maverick lawyer who enjoyed challenging authority and the Establishment over unfair laws and practices – at a time when consumers had few rights and many within British manufacturing and the media were suspicious of such an organisation. Rosemary McRobert, the former Deputy Director of the Consumer Association (which now trades as Which?), described him as "an extraordinary consumer advocate. If it hadn't been for David, we wouldn't have got so much consumer legislation on the statute books."

Born in Portsmouth in June 1929, David Edward Tench was the youngest of four children. His father, Henry, was a marine engineer who had served in the Merchant Navy during the First World War while his mother, Emma, looked after the household. Tench spent three years as a Quirister, or chorister, at Quirister School, which was part of Winchester College. He had a brief spell at Portsmouth Grammar before moving on to Merchant Taylors' School in Amersham in 1943. The move was precipitated when his father was ordered to help develop field kitchen-oil burners for the army.

Not overtly academic and uncertain which career path to tread, Tench left school at 18. However, upon his father's advice, he decided to pursue a career as a solicitor. He qualified before undertaking National Service in March 1952. In the Navy, he was posted to Malta, where he worked as a decoder and learnt Russian, reaching the rank of midshipman.

Military service completed, in February 1954 Tench became a junior partner in a private legal practice. The turning point in his life came in 1958 when he joined the Inland Revenue, working as a tax lawyer at Somerset House. His son Matthew described it as "his equivalent to university": while he was mingling with those of different social backgrounds his horizons were broadened and he gained a fresh outlook in areas such as art and politics.

It was at the Inland Revenue that Tench first came into contact with the fledgling Consumers' Association (CA), which had been launched in October 1957. The CA undertook what it was fond of describing as "honest fact-finding," empirical, comparative research into the functional worth of consumer durables. The CA's concern was with the design of goods from the point of view of efficiency, convenience and safety in relation to their price. Its mission was to educate and advise everyone, but particularly the mass market.

This, however, went somewhat against the grain in 1960s and '70s Britain. "So-called consumer associations devote their time to harsh criticism of British goods", the Daily Express seethed, accusing the CA of "paying to support a campaign against British exports, British industry and British employment."

Recommended to the CA's director, Casper Brook, by a liberal barrister, Keith Wedmore, who became a "guiding light" as well as a good friend, Tench's first work for the organisation was to collaborate with Edith Rudinger, the Editor of Consumer Publications, the Association's publishing arm. The Law for Consumers (1962) and The Law for Motorists (1963) were their first titles, followed by Wills and Probate (1967), The Legal Side of Buying a House (1965) and What to Do When Someone Dies (1969), all approachable, all appreciated and all best-sellers. The last three are still, in their constantly updated versions, staple reference books.

Tench had found his raison d'être. In 1969, he joined the Consumer Association full-time as a legal advisor following a call from Wedmore. The move transform his professional life: he became the public face of Which? during the 1970s and '80s and was particularly pioneering in two areas, using the media to get his message across, while at the same time lobbying intensively to change the law.

Once a week he joined Jimmy Young's radio show as "Legal Eagle", dispensing advice on consumer questions.Concurrently, he worked on That's Life with Esther Rantzen. The two had met on the consumer programme Braden's Week, where she was one of theresearcher/presenters. In 1973, when she took the Braden's Week format and turned it into That's Life, he became the programme's legal advisor, even making the occasional appearance.

They worked together for over 20 years; Rantzen described Tench as "the consumers' guardian angel", the acceptable face of the legal profession. His advice was always succinct and quotable, she said. It was while working on the programme that Tench coined the phrase "if a thing seems too good to be true, it probably is."

Aside from his high media profile, Tench became an active lobbyist, wanting to change the law to make it more "friendly" and to make complicated issues simple for all. With little idea how to set about changing laws, he started from scratch, learning the ways of parliament as he nurtured and developed what eventually became the 1971 Unsolicited Goods and Services Act; he and became adept at parliamentary procedure and the use of Private Members' Bills to push for reforms. Regarded as unconventional in his approach, he thrived on confronting the Establishment in areas he thought unfair.

Tench knew that the subtleties required to get a bill through parliament were many – "you have to keep your wits about you" – but he found it exhilarating work. Over the years, he was involved in some landmark legislation – what Lord Denning described, for example, as "the most important change in civil law" in his lifetime, the Unfair Contract Terms Act of 1977, part of whose success was in restricting what manufacturers could wriggle out of with their disclaimers of liability.

The most exciting political change Tench helped bring about was probably the House Buyers' Bill, a Private Members Bill which he helped the MP Austin Mitchell get on to the statute books. The bill, leading to the end of solicitors' monopoly of conveyancing, was enshrined in the 1985 Administration of Justice Act. That exercise constituted the most demanding four or five months of Tench's life. He was also proud of his work on the Consumer Safety Act (1978), the Administration of Justice Act (1985) and the Consumer Protection Act (1987).

On his 25 years of remarkable legislative success, Tench said modestly, "It's difficult for the government to be against issues of consumer rights because consumers are their constituents." He was awarded an OBE in 1987 and retired from the CA as Director of Legal Affairs in 1994.

Tench married Judith Gurney in August 1957; the couple met while he was serving as best man at the wedding of a friend, who was marrying Judith's sister. They had three children, Matthew, Emma and Dan. Tragedy struck when Judith died in 1986 at the age of 51. In 1988, Tench married Elizabeth Macdonald.

David Tench had extraordinary energy; he was organised in his work and erudite in his thinking, and had the great gift of identifying with "the other side" – the consumers and their needs. Rosemary McRobert described him simply as "an absolute one-off".

David Edward Tench, solicitor and consumer rights activist: born Portsmouth 14 June 1929; OBE 1987; married 1957 Judith Gurney (died 1986; two sons, one daughter), 1988 Elizabeth Macdonald (two stepsons); died 23 January 2011.