He’s a queer cove, Nigel Farage. When he was a boy, he says, he was bolshie, perverse, doolally – and normal. He still is all of those things, in spades.

Over the past year, things have really changed for the Ukip leader. He’s been walking taller, smiling even more. From a figure on the margins – horribly maligned, battling, largely thanklessly, for so many years – he has finally emerged into daylight.

Popular approval has forced the media and political establishment to take him seriously. Look at what happened after last Wednesday’s televised debate with Nick Clegg on the European Union. The “political commentators” were lining up to slap Mr Clegg on the back, but the great unwashed voted for Mr Farage (57 per cent felt he had performed best).

I have been filming with him for the past six months, and I feel rather like one of those chaps in Ice Cold in Alex who emerge from the Western Desert on wobbly legs, tired and emotional. Except I’ve had a hell of a lot more to drink. In fact, I’m having a dry month to celebrate.

For the record, yes, he drinks quite a lot; yes, he is very good company; yes, he’s a bit of a scallywag; and no, he is not at all cut out for a life in politics. This last point, I suspect, explains why he is so enormously popular. But the first question people ask is: “Did you like him?” I will delay replying, just to tease you.

The journey really started last summer, when I met him outside a pub in west London and asked him if he’d let me make a film about him. Mr Farage didn’t have one of those swanky phones that gives you emails and magically stores all your LPs. His phone had 10 numbers and a Go button. All the emailing and arrangements had been done through his lovely wife, Kirsten (yes, she really is his secretary). He sat there, suspicious, nursing his London Pride, sucking on his Rothmans, eyeing me narrowly, like a parrot who has been offered half a banana by a stranger.

I didn’t like him. Looking back, I think it was because I knew he didn’t like me. I was another snake-oil salesman; one of those smooth-talking media folk who have been beating seven bells out of him for the best part of 20 years.

Nevertheless, Mr Farage agreed to be filmed (I think Kirsten made him), and we were off. The first few spells were tricky. Mr Farage hates to be pinned down. His staff despair because he likes to do things on a whim, which makes filming, and most other things, tough to organise. Nor, at first, did he like being filmed. There were lots of hollow groans and eye-rolling. But there was something strangely endearing about his belligerence. He knew I had it in my power to make him look like an ass, but he wasn’t going to smarm up to me.

It was when we went to Europe together that I started to warm to him. I met him at a service station in Kent, at about 4 in the morning, and we headed off by car to the Channel Tunnel. He prefers to go to Strasbourg by car. Even though it takes ages, it gives him the freedom to go off-road and visit First World War battlefields (he enjoys his history). He desperately wanted to take me to Ypres.

Mr Farage, I realised, is a passionate man. He has a romantic attachment to history and Britain and Europe. Surprisingly perhaps, he really loves Europe (he’s worked for a French company; his wife is German) and clearly enjoys going there. More than anything, however, he is passionate about his political beliefs. When he speaks of liberty, he does it with a certain something in his voice and a glint in his eye.

I confess that I didn’t really understand the EU when I went there. I didn’t know who was who and which institution did what (do you know the difference between the European Council, the Council of Europe and the Council of the European Union?). I imagined that other people did understand the EU, but they don’t, unless they’re in the EU machine itself. Not even the senior political journalists and politicians I spoke to for the programme. And not even supporters of the EU.

Mr Farage, however, does understand it, and it offends him to the core. It was in Europe that I realised what an idealist he is and how principled he is. For example, he thinks that the global-warming scare is utter nonsense, and says so to whomever will listen, even though most savvy politicians know to toe the green line.

Mr Farage is also generous, once he gets to know you, with his time and friendship. It was touching to see how popular he is with his staff and others – even his political adversaries – at the EU. In this respect, he’s rather like Norman Tebbit, a man also depicted as a monster who is, in fact, one of the kindest, nicest men in politics.

Mr Farage says his political side flickered into life when he read John Stuart Mill’s On Liberty at school (Dulwich College). At 18, instead of going to university, he went into the City, and worked as a broker at the London Metal Exchange. This is revealing. Not only was he not sucked into the Left-leaning, Big State-loving intelligentsia, he was also plunged into commerce when Mrs Thatcher was in full swing, dismantling the old-boy network in the City.

Deregulation meant meritocracy. Working-class lads flooded in, and they were better dealers than the toffs. Mr Farage loved it. He may come across as posh Home County respectable (he was raised in Kent, where his father was a stockbroker), but, believe me, he has the heart and soul – and politics – of an Essex barrow boy. And his chums in the City, as far as I can see, are Essex through and through.

Again, filming in the City, I saw what a romantic Mr Farage is. He has a deep, emotional attachment to the story of the Thames, the first centre of world trade, and to the commercial City that grew up to service it. It’s an extraordinary story – the story of the making of the modern world. He is not a Little Englander. I’ve never met a man with a greater love of global free trade and the immeasurable ways it has improved our lives. This is the enlightened, big, free Mr Farage, which I really find exciting.

We expect to have control over our own lives, but the EU denies us that. The EEC (as it was) promised free trade, but we got an inward-looking protectionist club. Mr Farage is right on these things.

But at home in his village of Downe, in Kent, you see another side of Mr Farage. He was born there 50 years ago this week, has never moved out, and still lives round the corner from his mother, to whom he remains close. He’s been a regular at the George and Dragon for more than 30 years. He really does hang out with real people, in a way that David Cameron, Ed Miliband, Mr Clegg and co do not. Mr Farage has “normal” views, for good and bad.

And now for the bad. Ukip’s supporters are, as a group, quite some way older than those of any other party. They have plenty of noble old-fashioned values: a love of self-reliance, free speech, a wish to see the Government leave us with more of our money. But they also have some old prejudices. Born in the 1940s and 1950s, they grew up in a different Britain, when British people were called Robert and Elizabeth, and foreigners lived abroad.

Mr Farage shares their disquiet at the pace of change and would like to stop the clock. A real libertarian globaliser should love supermarkets and hate planning restrictions. But Mr Farage shares the timid conservatism of these supporters. He also shares their strong views on immigration.

But even when he’s wrong, he’s so less wrong than the rest of them. Compared with our career politicians, Mr Farage is indeed perverse, bolshie and doolally – and normal. That is why he is so popular, and that’s why I now like him such a lot.

'Nigel Farage: Who Are You?' is on Channel 4 tomorrow at 7.30pm