Tristan Garel-Jones, who has died aged 79, was a perceptive and astute member of the Thatcher government whips’ office, with such unerring political instincts that he won admiration even from his opponents in the Labour whips’ office on the other side of the members’ lobby as well as among his critics on the Conservative right- wing. The widespread belief that it was he who inspired the ruthless character of Francis Urquhart in the novel and TV series House of Cards sprang from the wit and subtlety he displayed during eight years as a whip.

But Garel-Jones also had the ability to win affection and trust. A wealthy man of great generosity, he drew his political strength from a complete lack of personal ambition for anything other than the advancement of his friends and the political causes in which he believed. Primary among the latter was the future of the European Union and, as minister of state at the Foreign Office, he was responsible for the 1993 legislation to ratify the Maastricht treaty that stoked the Tory infighting that eventually led to the 2016 referendum on withdrawal.

Personal mobile phones were only just becoming available at that time and the fact that Garel-Jones owned one on which he could display the treaty legislation in its entirety in order to bolster wavering colleagues was a source of great wonder at Westminster.

In a speech about the UK’s upcoming presidency of the European council in the second half of 1992, Garel-Jones suggested that the approach of John Major’s government would be “a persuasive mix of principle and pragmatism”. It was an elegant phrase in which he coincidentally encapsulated his own political approach.

Although he was a Tory “wet” – as Margaret Thatcher branded those who opposed her rigorous policies – and even voted against the government on the day of his maiden speech within weeks of first being elected in 1979, he was always loyal to his word. Thatcher knew he did not share her brand of Conservative politics, but trusted and liked him. After he became a whip in 1982 he once said, albeit with typical hyperbole, that he would “kill for Thatcher”.

Yet Garel-Jones was held personally responsible by many Conservative MPs for Thatcher’s downfall. On the night of the first ballot of Michael Heseltine’s leadership challenge in 1990 when Thatcher failed to secure enough votes for victory, Garel-Jones had organised a late night meeting after the Commons business closed at his home, an elegant Queen Anne house in Victoria.

Five members of the cabinet were among at least a dozen ministers present at what became known as the “Catherine Place conspiracy” and concluded, in Garel-Jones’ words, that “the game’s up” for Thatcher. She resigned the next day.

The irony was that after Sir Anthony Meyer’s “stalking horse” leadership contest the previous year, which Garel-Jones had helped defeat, it was he, as deputy chief whip, who asked to see Thatcher and told her that she needed to drop the controversial poll tax. “You have won easily this time, but remember there are 100 assassins lurking in the bushes,” he said.

He also wrote a briefing note for the chief whip, Tim Renton, saying: “I believe that this is the beginning of the end for Mrs Thatcher” and that the job of the whips was to manage that end without a party split. A further piquancy was provided by the view held in Thatcher’s own office that if she had followed the advice in 1989 of the outgoing chief whip, David Waddington, and appointed Garel-Jones as his successor, he could have saved her job in 1990. “I’d have got the old bat in,” he said himself later.

Garel-Jones became a close friend of Major. He identified Major’s potential when they were both whips and in 1988 was already thinking of him as a future party leader. However he worked for Douglas Hurd in the election that followed Thatcher’s resignation, remaining loyal to a promise made to Hurd during the 1986 Westland crisis.

His anxiety about this difficulty was assuaged by Major himself two days before he became prime minister. He stopped his car in the rain at midnight, having spotted Garel-Jones walking home from the Commons, and told him he understood and would have done the same. On becoming prime minister, he retained Garel-Jones at the Foreign Office, where he had been appointed that summer.

By the following year, however, Garel-Jones had decided he wanted to leave government and told Major as much. He was persuaded to stay on to oversee Maastricht and the UK presidency in Europe and although he could have joined the cabinet as secretary of state for transport, or for his native Wales, he stood down voluntarily in 1993 and went to the House of Lords after the Labour landslide victory in 1997.

He was disaffected by his party’s in-fighting on Europe – one of the more polite descriptions he used for eurosceptics was “maniacs” – and wanted to spend more time with his family. He was a literate and cultured man who collected modern Spanish art and European literature. Less enthusiastically, he also collected all the books published by parliamentarians during his years at Westminster.

Garel-Jones was born in Gorseinon, South Wales, one of two sons born to Meriel (nee Williams) and Bernard. His brother died in childhood. When his father was posted to India because of the second world war, the family moved to Llangennech, near Llanelli, where they lived above an uncle’s newsagent shop and Tristan attended the Welsh-speaking village school.

Tristan’s mother, an actor, suffered from bronchitis and in 1948 they moved to the warmer climate of Spain, where his father taught English at the school of architecture in Madrid. He later opened his own language school, La Casa Inglesa. Tristan was sent to preparatory school in Kent and then to King’s School, Canterbury, where he played “useful” rugby.

He joined his father as principal of the language school in 1960. There he met Catalina Garrigues Carnicer, one of the pupils and the daughter of a wealthy Andalucian landowner. They married in 1966 and moved to the UK with their four sons in 1970. Their daughter was born in 1981. Garel-Jones joined a merchant bank with Latin American interests and worked as a financial consultant until taking a post as aide to the Conservative party chairman, Lord (Peter) Thorneycroft, in 1978.

He had joined the party in 1970, standing unsuccessfully as parliamentary candidate in Caernarvon in February 1974 and Watford in the October election of the same year. He won in Watford in 1979. Arriving in the Commons he swiftly established himself as an astute political operator. He was a chain-smoking teetotaller, highly sociable and often to be found in the Commons’ bars, where little escaped his attention.

He was a founding member of the Blue Chip dining group of social liberals among the 1979 Tory intake and was appointed as a parliamentary private secretary to Barney Hayhoe in 1981, before becoming an assistant whip the following year. He wore mono- grammed shirts and handmade shoes and used his wealth discreetly to assist those in need.

He was a frequent host to political friends, notably Major, at his family home at the foot of the Gredos hills, 100 miles from Madrid. He was known as “the Member for Madrid Central” and once acted as official translator for Major on a prime ministerial visit to South America.

He was greatly amused to be invited in political retirement to become the bullfighting correspondent of the Spectator by Boris Johnson, the then editor, and used his first column to point out that there was no word in Spanish for “bullfight” or “bullfighter”. A humanist, he was a member of the National Secular Society.

He is survived by Catalina and their children, Julian, Inigo, Ivan, Sebastian and Victoria.

• William Armand Thomas Tristan Garel-Jones, Lord Garel-Jones, politician, born 28 February 1941; died 23 March 2020