“The reality is that I’ve been exceptionally fortunate,” concludes Sir Bill Cash when asked to reflect on his life. What he proceeds to cite as this providence is not – as might be imagined – the culmination of his long fight to restore British sovereignty. Rather, they are good health, family life and another monument to his perseverance for causes that appeared lost, the renovation of Upton Cressett Hall, the Shropshire manor house that he and his wife Biddy saved from ruin in the 1970s (they now live in a converted barn in the grounds, with their son and daughter-in-law residents of the hall).

Breathing life back into Upton Cressett’s sixteenth century bricks and beams has been one restoration, bending the British constitution away from its Brussels trajectory and back to its traditional course, the other. Although at Oxford, “cricket was my main interest apart from Biddy,” Bill Cash studied eighteenth century history (he’s the first politician of my acquaintance to conversationally slip-in a reference to the younger Pelham’s ministry). The fusion of his interest in constitutional history with the experience of his years practicing law is what made him the most potent – as well as unflagging – scrutiniser of European regulation.

Whilst a range of eminent legal opinion has been enlisted by the Eurosceptic cause over the course of its many battles, it is Cash who has been the Eurosceptic MP with the clearest, most encyclopaedic, understanding of the legal consequences of EU membership. He has been the in-house resource upon which likeminded MPs have drawn since the mid-1980s. Unsurprisingly, it was to a “star chamber” of lawyers and researchers chaired by Cash that the European Research Group turned for scrutiny of first Theresa May’s deal and then, over Christmas 2020, Boris Johnson’s agreement.

Yet, it was not with any clear focus to take back control from Brussels that Bill Cash first entered parliament in the 1984 Stafford by-election. Nobody at his selection meeting even asked him a question about the EEC. But he was not at Westminster long before he identified what was to be the great melody of his parliamentary career.

Concerned by the constitutional implications of the single market legislation that Leon Britten and Lord Cockfield had convinced Margaret Thatcher were so greatly in Britain’s commercial interests as to override any other concern, in June 1986, Cash put down his first amendment on sovereignty. “I’ve still got a copy of it” he tells me over the telephone. “It said ‘nothing in this Act shall derogate from the sovereignty of the United Kingdom parliament.’ Enoch Powell understood it and said to me ‘if you get this debate then I will support it.’ I had discussions with the public bill office and the Speaker. I was told I could not debate it. I complained on points of order but was told to sit down. Nobody else at the time was prepared to back me.”

Almost 34 years later, in January 2020, Cash’s sovereignty clause finally became law when it was enacted as section 38 of the European Union (withdrawal agreement) Act.

The length of Cash’s Commons career has meant that it spans the Westminster of the original “anti-marketeers” (politicians likes Enoch Powell and Sir Teddy Taylor), the Maastricht rebels of the early 1990s, and the generation of European Research Group leaders like Steve Baker and Mark Francois who entered parliament this century.

Cash was in a small minority when he first joined the European select committee in 1985 and began to realise as a constitutional lawyer just how pervasive European law was becoming. “We had a lot of extremely tempestuous meetings” he recalls of his tussles with the pro-Brussels mainstream, particularly the Harrow East MP Hugh Dykes, but “I’ve been on the committee now for 36 years. So, they’ve all disappeared – either in retirement or by joining the Liberal Democrats.”

Whilst Euroscepticism – let alone leaving the European Community – was still the minority view in the party, Margaret Thatcher was increasingly receptive to hearing the alternative perspective that Cash offered. “She asked about the chapter in the single market bill regarding economic and monetary union which was in brackets as an aspiration rather than a legal requirement. I gave her a very severe health warning that it would turn into something more dangerous.”

By April 1990, when Thatcher invited him to a Downing Street lunch, Cash did not hold back about the enormity of her task which, he suggested was “more difficult than Churchill’s. He was faced with bombs and aircraft. You are faced with pieces of paper.” Recalls Cash, “Geoffrey Howe was across the table glowering at me.”

It was about a very simple question, who governs this country?

Sir Bill is resolute that he never despaired, after all, “It was about a very simple question, who governs this country – and how?” But Thatcher’s fall and John Major’s signing of the Maastricht Treaty were the toughest moments. Maastricht, he still maintains, “was a complete capitulation to European integration. It was definitive because it was about entwining us in European government, removing our ability to govern ourselves not just in the commercial sphere but in other areas through a majority vote decided behind closed doors in the Council of Ministers without even a transcript.”

Yet, he never doubted that the Conservative party continued to be the only force able to rescue the situation: “I never had any interest in joining Ukip because I believed profoundly that the Conservative party was the vehicle for achieving the changes we wanted to resist European integration since ultimately it was a matter of legislation because we had to remove the European Communities Act 1972 if we were to make the changes.”

Despite failing to convince the shadow cabinet in 2008 of the need to support his sovereignty clause amendment to the Lisbon treaty (55 Tory MPs duly rebelled with him), he had a better rapport with David Cameron than Theresa May. “I would meet up with Cameron periodically. We discussed the fiscal compact. He was very courteous. Always asked extremely relevant questions. I said to him, ‘you’ve got to veto the fiscal compact.’ And he did.” With May, “we’d meet her quite often in Number 10, but there was never any substantive engagement. She would listen, but that’s as far as it went.”

It was Boris Johnson’s arrival in Downing Street that gave Cash hope that the substance of the 2016 referendum result would be honoured. “Boris was 100 percent” in support of the need for a sovereignty clause along the lines that Cash had so long been proposing: “the meeting on 17 October 2019 was critical. There was a lot of resistance to Boris adopting my proposals from the civil service and the Remainer establishment. But he prevailed against that, which was a mark of real statesmanship.” The gratitude he feels is widely spread, “I want to pay particular tribute to all those who have brought it together, especially The Spartans of the ERG and the electorate that decided they wanted Brexit done, to David Frost and Oliver Lewis and the members of our sovereign parliament who by 521 to 73 votes achieved the restoration of our self-government which is the greatest gift of all.”

Geoffrey Howe was across the table glowering at me

Both in the Commons and in personal conversations, Cash is especially fulsome in his praise for the prime minister: “he’s done it and he’s managed to achieve something that we were told was impossible. I was absolutely convinced that he wanted to achieve our sovereignty and that was the direction David Frost was given.” Indeed, the pronouncement by Cash and his ERG star chamber team that the trade and cooperation agreement did not compromise the Brexit fundamentals convinced many naturally sceptical Leavers that this was as good an outcome as they were likely to get. Carefully analysing the 1,246 pages of the deal intruded upon the Cash family Christmas last month, although he did manage to spend a contemplative moment on Christmas Day in the part-Norman chapel in Upton Cressett’s grounds. With Covid all around, the eighty-year-old Cash has been regularly popping-in there of late, “for a spiritual booster.”

Faith and the moral schooling he received at Stonyhurst have informed his political (as well as personal) life – restoring national sovereignty has not been its only theme. He also has a decades-long interest in Africa and poverty alleviation and was active in establishing and then chairing the all-party group for Jubilee 2000 debt relief for the developing world.

In 2014 his private members’ bill became the International Development (Gender Equality) Act. It ensured that allocation of aid money gave proper consideration to the rights and interests of girls and women wherever it was spent. As the then international development secretary, Justine Greening, acknowledged, “for assiduously steering his Gender Equality in International Development Bill through parliament over recent months, Bill Cash deserves the recognition of women everywhere.”

But the name of Bill Cash will always be as indelibly associated with the restoration of British sovereignty as the Anti-Corn Law League will be entwined with that of his famous ancestor, John Bright. Bright (whose biography Cash wrote in 2011) did hold cabinet office, but like Cash, his lasting achievements were secured from the backbenches. Now that Westminster is sovereign again – and given Cash’s age – is he ready to conclude that his work is done?

“Absolutely not!” he replies instinctively. The work of the European Scrutiny Committee (which he has chaired since 2010) will continue because “we need to maintain the legal and political analysis in order to retain the fruits of what Boris Johnson has achieved. There is a great deal to be done in using our sovereignty to resist the European Union attempting to crawl back from the deal. There are issues yet to be resolved on fishing and Northern Ireland. But these will come from political will and the ability to negotiate a successful outcome.”

Brussels, “will never give up on their desire to ensure we don’t compete effectively with them” he concludes, before adding, “I believe they will fail in that.” Indefatigable, realistic but unshakeably optimistic – Sir Bill Cash carries on, true to form.