Everyone has their moment. Edward du Cann, who has died aged 93, had his after the second general election in 1974. Although he had never held cabinet office, he was for a brief period a serious candidate for the leadership of the Conservative party. It was Du Cann himself, for reasons that were never quite clear, who withdrew on the grounds that his wife would not enjoy being married to a party leader (an early version of wanting to spend more time with the family).

But by this time, Du Cann was chairman of the 1922 Committee, the Conservative party’s parliamentary group. He had already been chairman of the party in 1965 and had joined the government in the latter days of Harold Macmillan. Having entered parliament for Taunton aged 32 in 1956, he became economic secretary to the Treasury (1962-63), then minister of state at the newly expanded trade and industry department. And in opposition after 1964 he was spokesman on trade and shipping.

That was an excellent run so far, especially when paralleled by a lucrative career in the City. He was also making a public name as a regular presence on the radio programme Any Questions? But a hiatus opened in Du Cann’s career.

He had been deputy to Edward Heath at trade and industry, standing at the threshold of the leadership. From 1963 onwards, Heath was the most serious candidate against the never far distant date of Sir Alec Douglas-Home standing down. If Du Cann sought to ingratiate himself with the coming man it did not work. Heath used the word “slippery”.

Du Cann was, if anything, a man of the right – over the aftermath of Suez, and on moral issues (he had worried about the growth of strip clubs) – and he had been an early opponent of entry into the Common Market on the reasonable, if narrow, grounds that it would harm horticulture. In 1967 he called for Britain to drop its application for entry into Europe. But how far early modest doubts about Europe influenced him against Heath and how far resonant dislike of Heath turned him permanently off Europe is a nice point.

He was famous at this time as a businessman, inaugurator of the unit trust with his Unicorn Group. In 1973 Heath coined the phrase “the unacceptable face of capitalism” (and directed it at Lonrho, on whose board Du Cann sat; he became chairman in 1984) and probably had more reservations about business and its ethos than any Tory leader since Stanley Baldwin. Then again they were different types, Heath brusque, with the outlook of a meritocrat without social connection, Du Cann sleek, polished and given to flattery.

Heath was not, then, happy on becoming Tory leader to inherit from Douglas-Home a new party chairman whom he could not immediately dispense with. What followed proceeded from the logic of that dislike. Heath sacked Du Cann as soon as he could – in 1967 – and offered him neither shadow office then, nor substantive office in 1970. Conversely, Du Cann’s election as chairman of the ’22 expressed parliamentary discontent with a struggling prime minister.

It was natural enough when Heath, confronting a perplexed electorate and losing two elections in a year, should find Du Cann prominent among those moving against him. Hugo Young, in his admirable book on Margaret Thatcher, One of Us, describes Du Cann at this time as “having something of the American political boss about him”. He was near the top of his business career, untouched by the mistakes of the Heath government, yet as a former chairman he had cabinet equivalence. His position was a little analogous with that of Michael Heseltine after his 1986 resignation – whatever was bad for the leadership advanced his position.

Not that loathing for Heath had hindered the administration of unguents. During the October election he had told Heath before some candidates: “You do not only lead but you command the party, you command more than men and women. There is no one here who does not reflect your own devotion to our cause ... we know that we can count abundantly on you, equally you know that you can count on us.” Other words soon after – “Do you know, dear boy, I think I may be Ted’s only remaining friend” – spoke more of the truth.

The son of Charles, a writer turned successful barrister, and his wife, Janet (nee Murchie), Edward attended Woodbridge school in Suffolk, then took a wartime degree in law at St John’s College, Oxford, before serving on a Royal Navy motor torpedo boat. After the second world war he worked for an investment firm while climbing the Tory ranks. He stood unsuccessfully in two elections, Walthamstow West in 1951 and Barrow-in-Furness in 1955, before succeeding in Taunton the following year.

In 1975 his own candidacy for the leadership came into the frame. It seemed like serious politics, with “Du Cann for leader” a chattering topic for the press, while he worked hard to cultivate the wider party, promising it a greater say in future leadership contests. Then quite suddenly, he pulled out. Possibly his business position, always frailer and more dependent on the patronage of the likes of Tiny Rowland than the Rolls-Royce front suggested, inhibited his candidacy. Most likely, he discovered that he had quite a few enemies.

Instead, from the offices in Milk Street of the failing merchant bank of which he was chairman, Keyser Ullman, he assembled the camarilla – the “Milk Street mafia” – that promoted Thatcher. His role was smaller than that of Airey Neave, who ran the Commons campaign. But he started the ball rolling, doing so not as any kind of Thatcherist but as an enemy of Heath.

The rest of Du Cann’s career was anti-climactic or worse. He continued as chairman of the ’22 until 1984, but he got no ministerial job from Thatcher, settling in the way of dignified retreat for the chairmanship of the Treasury select committee. He was knighted in 1985, and left the Commons in 1987.

As for Du Cann’s business career, it came dreadfully unstuck, stripping him of much of his wealth and leaving him in dispute over an unpaid mortgage. He had always been more of a business advocate in politics than a serious business force himself. A Department of Trade and Industry report into the failure of Keyser Ullman adjudged him to have been “incompetent” as chairman.

He resigned as a director of the mortgage broker Homes Assured just before it failed in 1989 with debts of £10m. Two years later he quit as chairman of Lonrho when the DTI began proceedings to disqualify him as a company director.

In 1962 he married Sallie Innes, and they had two daughters and a son. The marriage was dissolved in 1990 and he then married Jenifer Cooke, who died in 1995.

He published his autobiography, Two Lives: The Political and Business Careers of Edward du Cann, in 1995. In his later years he lived in Cyprus, where he invested in a vineyard in Lemona.

His children survive him.

• Edward Dillon Lott du Cann, politician and businessman, born 28 May 1924; died 31 August 2017