Four years ago, Neil Herron was a market trader who also rented out a few properties for extra cash. Yesterday, he launched his campaign for election to the European Parliament. He tells Nick Morrison why his journey isn't so strange after all.

It's curious how our fates can turn on seemingly innocuous events. A bizarre coincidence, a chance meeting, an off-the-cuff remark - these apparently random happenings can dramatically alter the course of someone's life.

For Neil Herron, his life-changing moment came the day, four years ago, when a trading standards officer walked up to his wet fish stall and told him to stop using his imperial scales, otherwise they would be confiscated. Outraged at being told to use a metric system which meant nothing to most of his customers, he wrote a letter to his local paper.

"If people came and asked for goods in metric, I would sell them goods in metric, but they didn't, and I was not going to have my business affected by bureaucratic interference. I had dual purpose scales. It was not my job to educate the public in the metric system, and for the Government to turn around and say all the kids know metric is bollocks," he says.

Four days after his letter was printed, trading standards officers returned to the Sunderland market and took away the imperial scales used by greengrocer Steve Thoburn. So began the Metric Martyr case which led all the way to the House of Lords, saw them appear on TV and in newspapers throughout the world, and yesterday saw Herron launch his campaign to be elected as an independent to the European Parliament.

He has sold his three wet fish shops, and his greengrocer's stall, and the properties he used to let out for extra cash. Today, he occupies a cramped first floor office in the centre of Sunderland, rented from his long-standing insurance broker, and it's from here that he directs the Metric Martyr's Defence Fund, supported by voluntary donations and of which he is now a salaried employee.

A map of the UK on the wall is studded with drawing pins, each representing a supporter for whom Herron's campaign against bureaucracy, regulations and, above all, the European Union, has struck a chord. But as we talk, it becomes apparent that what is remarkable is not that this 41-year-old Bruce Willis lookalike abandoned his previous life to devote himself to campaigning, but that he has taken to it so easily.

'It was the most rapid learning curve, but I knew from the first day what difference I could make. It was crystal clear, like being shot with a diamond bolt," he says. "It just seemed so natural, that this is what I had to do, and I was never daunted by the enormity of the challenge. I never thought about it, I just had to do it."

Before that trading standards visit, he says Europe barely entered his mind. "When you are up at four o'clock in the morning and you work at 100 miles an hour, or even 140 kilometres an hour," he's unable to resist a dig at the metric obsession, "you haven't got any time to think."

He can only remember voting twice before: once for Labour and once for the Tories. But as soon as the challenge appeared, he threw himself into it with gusto.

"When it happened with the scales, and you go through the doors and into the corridors of power, you realise you can make a difference by standing up against the system," he says.

And it makes you think that maybe it wasn't chance at all, and there couldn't have been a different outcome, with Herron still on his fish stall. Maybe it was inevitable, that when an organisation which seeks to impose conformity comes up against someone as obstinate as him, there will be trouble.

"Steve used to say I was the biggest shit-stirrer he had ever met. He knew he was the victim, but he said he was going back to work, I was the one who would have to handle all the Press," Herron says. He sees his campaign's appeal as the "David against Goliath syndrome," where he speaks for the ordinary men and women, an articulate graduate and father of two, who talks partly in no-nonsense terms and partly in newspaper headlines.

"I know what I felt in my gut was what everybody else felt. There are a lot of people out there who want somebody to stand up for them. It is somebody speaking their language, taking a very pragmatic and common sense approach," he adds.

"What I stand for is endorsed by many tens of thousands of people, which is that we're not prepared to be governed by Brussels. We can't be governed by people who we can't remove from office, and here we have an organisation that is not democratically accountable to the people whose lives it affects."

As a committed anti-European Union campaigner, he justifies his decision to seek election to the European Parliament as an opportunity to fight from the inside. Maybe it will also release the campaign from its reliance on voluntary donations.

"At the moment, we're throwing stones at the building, trying to smash a few windows, but you are most effective inside the building, because then you've got an electoral platform and you can't be ignored."

He says the question of withdrawal from the EU is one for the British people, once they have all the facts in front of them, but his principal objection seems to be not the EU as such, rather the way it is run, bureaucrats who cannot be voted out of office imposing their decisions. Having said that, he can't imagine it being run in a way he approves of.

In any case, he feels the EU will soon cease to exist, on the grounds it is built on sand, without proper democratic institutions, and will be unable to continue now it has 25 members, although this may be wishful thinking. More pertinently, he feels the British public were sold the EU as an economic venture, and have never had the chance to say whether they want political integration or not.

He could have thrown in his lot with the UK Independence Party, but says he would rather work as an independent. It would also involve taking a stance on other, non-EU, issues, although the difficulty of this approach is illustrated in a letter he picks at random from that day's postbag.

After congratulating Herron on his campaign, the writer goes on to say we should say no to GM crops. So where does he stand on GM crops? "At the moment I'm opposed, but I would have to look into it and take a view," he says.

In a similar vein, he opposes a regional assembly. He says it's an extension of the Metric Martyr campaign, and maybe those who support imperial measures will all reject an assembly, but then maybe it's possible to agree with him on one and not the other.

"The No campaign against the North-East assembly is a natural progression of the Metric Martyr, which was opposition to rules and regulations by people we can't remove from office," he says.

"People who are opposed to regional government tend to be opposed to further integration with the EU, and there is a EU dynamic - it needs to work with regions, not nations. We didn't ask for regional government."

Of course, if the referendum later this year goes in favour, we will have asked for it, but he says the chances of this "are about as much as Newcastle winning anything, although I shouldn't say that."

The Metric Martyr himself, Steve Thoburn, died earlier this year, at the age of 39. The coroner's report said the father of three had an underlying heart condition, and Herron says he doesn't feel the stress of the court battles contributed to his friend's death. Similarly, his pledges to his fellow trader were to recover his scales and get his conviction quashed - he managed the former two days before the cremation, and is still working on the latter. But there's no suggestion there's any hint of vengeance about continuing the fight.

Rather, it could have been what Herron was born to do. "Everybody who has had a run-in with bureaucracy and authority has felt hopeless," he says. "I'm just the mouthpiece of ordinary people who feel the same way as I do. I just don't like being told what to do."