He is dismayed by Sir Keir Starmer’s pursuit of a closer relationship with Brussels and by Chancellor Rachel Reeves’s economic decisions. “The idea that we are a wealthy country is complete nonsense,” he warns. “In terms of people’s prosperity we are in dire straits.”

He has a simple diagnosis of why Brexit has yet to deliver longed-for growth: “We won a revolution but left the establishment in charge who had done everything possible to frustrate it.” In his supermarket days he travelled the world – even venturing into the Amazon region in search of soya beans – and witnessing the surging growth of emerging economies convinced him Britain was missing out on true prosperity.

He remembers saying in the 1990s: “We need to start loading planes up to take people out to Asia to see what real growth looks like because they have no idea.” Britain’s “relative decline”, he decided, was a “serious problem”. The nation needed a different order of growth in order to maintain the NHS.

Years of visiting businesses across the country convinced him British enterprises could rise to the challenge of life outside the EU. “They were quite capable of doing anything if they were set free,” he says. “What I knew was the legislative burden of the European Union was just going to grow and grow.”

In the run-up to the referendum he visited embassies. In France, he remembers, he “just got vitriol” – and at a dinner at the German Embassy he found a group of establishment figures “very clearly plotting” to undermine Brexit. He also remembers a senior BBC player being “outrageously prejudiced against Brexit”.

“I was just appalled,” he says. “I gave a speech at the end and walked out.” When he decided to share his conviction that Britain could have a brighter future outside the EU, from a personal career point of view, he had a “deep suspicion that it might not end well”. His stance drew the fury of Downing Street, he says, and Boris Johnson described his treatment as “scandalous”.

Post-resignation, he took a role in the Vote Leave campaign but did not consider it mission accomplished when the country backed Brexit. Mr Longworth and Richard Tice – now the deputy leader of Reform UK – launched a new pressure group, Leave Means Leave, to ensure Brexit became a reality.

Years of gridlock followed as Theresa May – a “terrible Prime Minister” – tried to negotiate a deal with Brussels which could command the support of Parliament. Meanwhile, the campaign for a second referendum to reverse Brexit was gathering support. Coincidentally, Mr Tice and Mr Longworth had a little more in common than a desire to cut the cord with Brussels, for they had both previously studied at the University of Salford.

Mr Longworth remembers: “I did go back to Salford to do a speech for the alumni and pointed out that had Salford not given us
such a brilliant start in life Brexit may never had happened.” The UK had still not left the EU by the time of the 2019 European Parliament elections.

Mr Longworth accepted an invitation from Mr Farage to stand for election and the newly formed Brexit Party topped the poll. When he arrived in Brussels he never doubted that Britain was better off outside the EU project. The country had only become a member in an “act of despair”, he argues.

“The whole objective was to create a federal state and Britain misunderstood this again and again. We should have either got in there right at the beginning, and we could have shaped it to our own liking, or we should have kept well out of it and never joined.”

However, his relationship with Mr Farage ruptured and he lost the whip for “repeatedly undermining” the Brexit Party’s general election strategy. Mr Longworth had argued that the party should concentrate on winning 20-30 seats. “My number one priority was getting Brexit done,” he says. He feared Tory leader Mr Johnson’s chance of winning a strong majority in the 2019 Westminster election was under threat, and Brexit itself could be at risk.

Mr Longworth joined the Conservatives and the Tories won a landslide – but he was dismayed at the Johnson premiership. “He got Brexit done but in every other way he was a disaster for both the country and the Conservatives,” he says. “He caused the Boris-wave of migration – utter disaster. He pushed forward the net zero madness – utter disaster.”

Mr Longworth has not yet decided which party he will back in the next election – but again he is concerned that the centre-Right vote will split and Labour may once more win power, potentially with the help of the Liberal Democrats. “It’s absolutely essential all parties on the Right put the national interest first, because Britain is going to be ruined,” he warns.

“And if they don’t, it demonstrates what they are really made of, which is personal ambition and power-seeking.” In Sir Keir’s “utterly pathetic” efforts to “reset” relations with the EU he sees an echo of Edward Heath’s original push for membership. “It’s an act of despair that he’s cosying up to the EU, giving away things while getting nothing in return,” he says.

One of his great concerns is that Britain has been led by people with minimal business experience. He argues that politicians could actually learn much from supermarkets. While super-markets face intense competition and survive through extreme efficiency and championing the interests of the customer, Whitehall has no “internal competition whatsoever”.

Adamant that supermarkets are a force for good, he says: “Before supermarkets grew into what they are now, manufacturers dictated to consumers what they should have – now supermarkets act as the advocates for the consumers, effectively telling the manufacturer what to make. It changed the whole dynamic of the market.”

He grew up in Bolton “in a terraced house next door but one to a mill”. His father served in the RAF and managed a dairy, and Mr Longworth became the first in his family to go to university, studying environmental sciences and then
atmospheric physics. When Keith Joseph – widely seen as Margaret Thatcher’s intellectual guru – spoke at his university in front of a “very rowdy” audience, the future Brexiteer was politically electrified. “He was a genius,” he remembers. “He was amazingly inspiring.”

His great fear today is the UK gets locked in an economic “doom loop” – but his experience of seeing Britain escape the quagmire of the 1970s fuels his hope that better days are ahead.

He argues “just one thing alone” would transform the economy, and “that’s scrapping net zero madness”. He wants a new era of drilling for North Sea oil and gas, with fracking tapping into Britain’s underground energy reserves. If the Government went down this path while shrinking the state and cutting taxes, he says, “people would be amazed how quickly things change”.

He now chairs the Independent Business Network which champions family-owned businesses and has the mission of seizing “the opportunities Brexit provides”. This entrepreneur and campaigner knows that speaking your mind can come with a great cost but he relishes his freedom and has great ambitions for this country.

Does he want to stand for election again?

No, but, “if you want to put me in the House of Lords as business spokesperson, I’ll accept that reluctantly, but that’s highly unlikely to happen”.