Alistair Lexden is the Conservative Party’s historian. He was political adviser to Airey Neave from 1977 to 1979 and regularly discussed Ulster politics with Ian Gow (over the inevitable White Lady cocktails) in the years that followed, until his murder.

The IRA bomb went off at 8.39 a.m.on a sunny Monday morning. It had been placed overnight under Ian Gow’s Austin Montego immediately beneath the driver’s seat. It detonated shortly after the car had started to move with Gow at the wheel. He died ten minutes later. His adored wife, Jane, was a helpless spectator. Over the days and weeks ahead she was to draw much solace from the deep Anglo-Catholic faith they had shared. Gow himself had been a lay reader. His brilliant, many-sided life of service was cut short at the age of 53.

The scene of this terrible IRA crime was the Dog House in Hankham, a village in the Eastbourne constituency which Gow had represented since February 1974, attracting ever deeper affection as the years passed. Despite its gloomy name, his charming constituency home had hitherto been a place of fun and laughter, much of it induced by Gow himself who dashed around the tennis court and swam in the pool with tremendous gusto every weekend. He had earlier drawn on his apparently limitless reserves of energy in the post that earned him political immortality: PPS to Margaret Thatcher from 1979 to 1983. She was only person at Number 10 who worked longer hours than he did, arriving every morning at 6.30am regardless of how late he had departed the previous night.

In the late-1980s Gow put himself high on the IRA’s target list by the frequency and eloquence with which he condemned its terrorist campaign and proclaimed his determination to ensure that Ulster remained part of his country in accordance with the democratic wishes of its people. He believed that terrorists must be defeated and their capacity to threaten democracy eliminated. He regarded it as utterly intolerable that their representatives should be considered for places at the negotiating table, still less regarded as possible partners in the government of a part of the country they had sought to unite with another state. In his view a stable, long-term future for Ulster could only be achieved by governing it as all other parts of his country were governed: through elected representatives accountable to the Westminster Parliament. There was no place for devolution in his political creed.

He showed unfaltering courage in the face of grave danger. He refused any form of special personal protection. A few weeks before his death, when pressed to vary his journeys and check under his car, he replied characteristically “Certainly not. I am at less risk than any serving officer in Her Majesty’s Royal Ulster Constabulary—and anyway, I wouldn’t know what to look for”.

The immense joie de vivre which he displayed to his innumerable friends at the Dog House and elsewhere was not immediately apparent at first meeting. To strangers he gave the impression of being a survivor from an earlier age, out of place in Thatcher’s brash, fast-changing Britain. At Westminster he invariably wore a three-piece suit cut in the style of the 1950s and adorned by a gold watch-chain. Thus attired (even at the height of summer) he carried into political life the solid professional demeanour acquired in his earlier career as a partner in the most old-fashioned firm of solicitors in London.

This spectacle of utter probity was, however, a little diminished by Gow’s marked physical resemblance to the most celebrated of his Eastbourne constituents, Dr John Bodkin Adams, an Ulsterman whose elderly female patients had a habit of dying soon after they had made wills in his favour; no fewer than 132 of them remembered him generously, making him a rich man and precipitating a murder trial which resulted in an unexpected acquittal. Gow was not in the least abashed by instances of mistaken identity, fondly recalling the £5 donations which “the good doctor” made to Tory funds at each election.

His conversation, when first heard, reinforced the impression of a period piece. “The Queen’s First Minister desires me to say that she would be grateful if you could wait upon her at Chequers this very Sunday”. A new and rather reluctant member of Mrs Thatcher’s speech-writing team was startled to be summoned to his duties in these florid terms. In the company of his fellow MP and friend, Michael Brown, he called on the Mayor of Blackpool during a Conservative Party Conference. “Would Your Worship oblige us by robing himself in full civic splendour? Does Your Worship retain his chain of office upon his person when he is in night attire?” Such anecdotes abounded at Westminster.

Nothing, however, would be more mistaken than to derive from them the conclusion than he was a pompous man. Behind the old-fashioned spectacles (no mere glasses for him) impish eyes gleamed. He fell naturally into the part of gracious relic from an earlier generation—and played it superbly with endearing self-mockery. A London bus( or rather omnibus) provided another stage for his comic talents. Experiencing this mode of transport for the first time in 1989 at Michael Brown’s suggestion, he declared to bemused fellow travellers that it was astonishing good fortune to be able to proceed in such a commodious vehicle for a mere fifty pence.

He adapted his rich gift for humour to differing circumstances. In Parliament he was gently sarcastic about members on both sides of the House. On 21 November 1989 it fell to him to make the first speech to be televised, though ironically he strongly disapproved of the televising of proceedings. After some hilarious comments delivered in deadpan fashion about the absurdities of the public relations business, he turned to the harbour that was being built in Eastbourne. “When the harbour is completed”, he declared, “there will be berths for 1,800 small boats. Miners from Bolsover, entrepreneurs from Newham North West, refugees from Brent East, grocers from Old Bexley, all these and many more will be able to moor their boats or seek refuge from the storm in the new Eastbourne harbour”.

His wit, charm, and taste for long hours—coupled with a quick mind and deep devotion to Commons life—provided him with the talents that enabled him to become Margaret Thatcher’s principal Tory confidant and counsellor during her first government—and the greatest PPS of all time. In choosing him as her closest aide in 1979, “I made my last and best appointment”, Mrs Thatcher later wrote in her memoirs. His devotion to The Lady, as he was the first to call her, became legendary. Alan Clark, with whom he conspired frequently, noted in his diary on hearing the news of Gow’s murder that “Ian loved her, actually loved, in every sense but the physical”. It was thus a labour of love in which he was engaged for the following four years sustained, as he wrote to me at the outset, by the absolute conviction that she was destined to become a great Prime Minister.

This was the happiest time of his life for he knew that his work was crucial to Mrs Thatcher’s success, particularly as regards her controversial economic policies to which he was totally committed. His close lifetime’s friendship with Geoffrey Howe,then Chancellor of the Exchequer, added to the importance of the role he played. His capacity to carry it out supremely well was powerfully assisted by the popularity that he enjoyed on all sides of the House and by the readiness with which he dispensed drinks, particularly his trademark cocktails, White Ladies (two parts gin, one part Cointreau, one part lemon juice) with which he prised many secrets from his colleagues.

In a passage of his perceptive biography, Margaret Thatcher: Power and Personality (2013), Jonathan Aitken ,who knew Gow well, identifies “three great strengths” which explain why he became so formidable:

“The first was his encyclopaedic knowledge of the Conservative Parliamentary Party, whose MPs affectionately nicknamed him ‘Supergrass’. He reported their murmurings and mischiefs with a humorous fidelity that appealed to Margaret Thatcher’s enjoyment of gossip, and kept her attuned to her power base with a depth of understanding that was never again achieved after Gow left her inner service with a ministerial promotion in 1983.

Second, he achieved a personal rapport with her that was unequalled by any other political colleague. Over late-night tumblers of Famous Grouse whisky in the flat above No 10, he reinforced her own convictions. For in every major policy area, from relations with the EEC to balancing the public finances, Gow was a hardliner with the driest of dry views, which were often more arid than her own.

Third, he was a straight arrow who won her absolute trust. He exercised immense influence over her in matters that ranged from who she should invite to dinner to who would make good ministers”.

Gow himself did not make a good minister in the housing and Treasury posts outside the Cabinet to which he was appointed after 1983. Michael Brown, who shared his Commons office, has no doubt that “his departure as her PPS for ministerial office was a mistake. She felt he deserved promotion but he hated ministerial life”. The job he wanted, but never got, was at the Northern Ireland Office where Airey Neave would have made him a Minister of State in 1979 if he had lived (and in those circumstances of course he would never have become Mrs Thatcher’s remarkable PPS). Together Neave and Gow, who got on together extremely well, had formulated a policy—with some help from me—to draw Northern Ireland fully into British political life at Westminster and kill off devolution by stealth. This was the Ulster policy from which Gow never departed, as Charles Moore’s brilliant biography of Margaret Thatcher makes clear. Her failure to implement such a policy was the one shadow on his happiness as her PPS.

That shadow darkened much further when Mrs Thatcher took the entire political world by surprise by signing the Anglo-Irish Agreement in 1985. It gave the Government of the Irish Republic a direct role in the affairs of Northern Ireland over which it claimed sovereignty. Parliament was told nothing in advance about this extraordinary demarche. It was the secret creation of the Cabinet Secretary, Sir Robert (now Lord) Armstrong and his counterpart in Dublin, designed to set the scene for the ever closer union of the two parts of Ireland. It was wholly incompatible with the Ulster policy with which Gow was identified and he resigned his unenjoyable Treasury post.

His almost total absorption in Ulster affairs thereafter made him a marked man among the criminal ranks of the IRA, leading to his murder 25 years ago today. Airey Neave’s murder eleven years earlier had altered the course of Conservative history by leading to the cancellation of a strong Unionist policy and releasing Gow for his greatest work at No 10. Did Gow’s murder alter it even more fundamentally by removing the one person who could have prevented Margaret Thatcher’s downfall four months later?

In an article in 2010 marking the 20th anniversary of Gow’s death, Bruce Anderson wrote: “The man in charge [of her re-election] was her then PPS, Peter Morrison. He was bibulous, complacent, useless… In the first ballot, she was four votes short of an outright win…If Ian had been alive, he would have found her the votes. He himself would have provided one of them, while persuading the other three—and more… Doubters would have been lured to the Cavalry Club and filled up with White Ladies… He would have secured her re-election”.

Whether she would have regained sufficient authority in the Party to govern successfully is a question to which it is perhaps more difficult to give an emphatic answer.

Ian Gow’s devoted friend, Geoffrey Howe, gave a powerful address at his memorial service on 22nd October 1990. He concluded: “Ian’s fearless independence, his unshakeable loyalty, driven as they were by deep emotions, stand as a model to all who grieve his tragic death. One of the most respected, warm-hearted and courageous politicians of his generation has been struck down by the brutal extremism which he so forthrightly and consistently deplored. In this place and on this day we may be sure – he may be sure – that Ian’s oh-so-full life was not in vain. Our resolve in the face of evil will never weaken.” Twenty-five years on that must remain for us the chief lesson of this wonderful man’s life.