Lady Oppenheim-Barnes obituary | Politics

Sally Oppenheim-Barnes, who has died aged 96, was the former Conservative minister of state for consumer affairs and a politician with an intuitive understanding of what was of concern to the public in general and her constituents in particular. She had recognised the growing importance of the rights of the customer in the booming Britain of the 1960s and on arrival in the House of Commons in 1970 immediately set about making the subject her own.

She was a bright, brash, assertive woman who made full use of three years’ Rada training for the stage and who was famed for an eye-catching wardrobe, wrist-rattling jewellery and a large helmet of blond hair that would not have been out of place on the set of Dallas. She knew what she wanted and set out to get it, and having decided on a political career (early marriage and motherhood having put paid to acting), she took advice on how to proceed.

A Tory since childhood, who had cried when Churchill lost the 1945 election, she joined the party aged 22 and was advised by Conservative central office that she needed to demonstrate an understanding of contemporary society to stand any chance of selection as a candidate.

She did as instructed and spent three years as a social worker, helping immigrants with health issues in Hackney, east London, a world away from her family home in Finchley, north London, where her husband, the millionaire property magnate, Henry Oppenheim, was a prominent member of Finchley Conservatives and helped select Margaret Thatcher as the party candidate in 1958.

Even so, it was at her sixth attempt – having been shortlisted across the country from Carlisle to Clapham – that she was chosen in 1968 for what should have been a safe Labour seat.

Unexpectedly capturing Gloucester for the Tories – wearing a headscarf and wielding a shopping basket – she defeated the Labour cabinet minister Jack Diamond by a majority of just over 1,000. In an eve of poll leaflet she declared herself an opponent to European membership, in contrast to the sitting MP, and would later be one of the few Tory MPs to vote against the principle of the UK joining in accordance with the outcome of a constituency poll.

On arrival in the Commons, she was on her feet within weeks, airing her interest in what would come to be known as consumerism; within months she was asserting her belief that competition in the marketplace was the best protection for the consumer, but nevertheless asking a government minister additionally for progressive legislation. Edward Heath appointed her as a junior spokeswoman in opposition to Labour’s newly created Department of Prices and Consumer Protection after the October 1974 election, and the following year Thatcher made her a member (and the only other woman) of her shadow cabinet.

On Thatcher’s election victory in 1979, appointed as ministerof state for consumer protection, and made a privy counsellor albeit not in the cabinet, she abolished the Price Commission – replacing it with the Office of Fair Trading – ended all state funding for local consumer advice centres, but doubled spending on Citizens Advice bureaux.

She had long resisted metrication and successfully delayed its implementation, and now scrapped the Metrication Board and announced that the use of metric measures could be voluntary. Her interest was in defending both the shopper and small independent retailers, and her causes included attempts to ban rogue estate agents, end fixed fees for architects, remove opticians’ monopolies and secure safety regulations for furniture.

In 1981 responsibility for the Monopolies and Mergers Commission and tourism was added to her brief. She would say later that tourism was always her favourite industry: it brought money into the country and never asked for any.

Henry had died in 1980, and she stood down as a minister citing family reasons in 1982. The following year her son, Phillip, joined her on the backbenches as Conservative MP for Amber Valley. By the time she resigned as an MP in 1987, she had increased her party’s hold on the Gloucester seat to comfortably over 12,000.

She then chaired the National Consumer Council for two years, a government appointment that was initially suspected as attempt to end NCC criticism of Westminster policy, but she continued to demonstrate an independence of mind. She arrived in the job having circulated to staff a speech she had made 12 years earlier declaring how she wanted more effective consumer protection and how she believed the consumer should be the king or queen of the marketplace.

In her view there was still “much to be done” when she left the post, on her elevation to the House of Lords in 1989, where she was a member for 30 years.

Born Sarah in Dublin, she was the only child of Jeanette and Mark Viner, a trained diamond cutter and a member of the Viener family that established the original Viener cutlers and silverware makers in Sheffield in 1908 and held the royal warrant as Viner’s Ltd for King George V. The family returned to Yorkshire where the child attended Sheffield high school. She then went to Lowther college (a former public school that closed in 1982) in north Wales, followed by Rada, in London. She married Henry in 1949, and changed her first name to Sally in 1968.

She was unapologetic about her considerable wealth, once breezily telling the Daily Express with some justification: “There’s a lot more to me than a rich bitch.” She was far from a feminist but, like Thatcher, did not consider her gender a bar to achievement. She relished pointing out that Marx, Lenin and other revolutionaries were chauvinists who “left their wives slaving over a hot stove”.

She was a director and major shareholder of a family company with an extensive property portfolio and was left well off when Oppenheim died. A main board director of Boots (1982-93), she continued to maintain business interests. She used happily to admit that Harrods was her favourite store and laughed off frequent jibes she attracted from Labour MPs.

In 1984 she married John Barnes, the managing director of a missile components factory. He died in 2004.

She is survived by the three children of her first marriage, Carolyn, Rosanne and Phillip.