Once in a while, when I am not thinking straight, I seriously consider buying a wreck of a classic car and doing it up myself, in my little garage, with my own fair hands. After all, I have seen that bloke on the Discovery Channel restore his E-type Jaguar and it did not look difficult.
"Okay, now for the paintwork," he would say. "First, you simply rub down the old paint." Then he would demonstrate with a couple of strokes of wet 'n' dry before the camera would fade and return to a shot of him standing beside a shiny, bare-metal Jaguar. "Then you need to cut away and replace the rusty metal." Again, he would demonstrate by beginning to cut a piece of rust away with a pair of tin-snips before the camera would fade again.
Of course, what they do not show, because it would make for harrowingly tedious TV, is the two months between each fade where a team of specialists, using expensive equipment, endured acid burns, barked knuckles, frayed nerves and hours and hours of dispiritingly slow progress for which they were paid several times more than the car was worth.
Working on old cars involves long, cold, winter nights in draughty lock-ups, financial ruin, hernias, ulcers, marriage breakdown and, finally and inevitably, bankruptcy. And that is just taking the thing apart. So why do so many find DIY restoration so tempting?
"It's all about that satisfaction of knowing that you have done everything yourself, every nut and bolt," Mike Coman, of the Leeds College of Technology's restoration department tells me. "Then one day, at the end of it all, you drive down to the pub on a sunny day, park it in the car park and someone comes over and says, 'Flippin' heck, it's a long time since I've seen one of those. It's lovely'."
Mr Coman is among the organisers of the Restoration Theatre, an annual workshop among the main attractions at the International Classic Motor Show at the NEC (8 and 9 November). Leeds College, like many technical colleges, runs full and part time courses in car restoration, teaching classic-car nuts how to go about rescuing their beloved wrecks from the clutches of the scrap yard.
"At the show, we'll be demonstrating the various techniques involved in restoring a classic car, including lead loading, a way of filling the gaps between panels with lead so you don't get the cracking of plastic fillers. That's a real black art.
"We'll also be doing gas welding, showing how to weld aluminium, which many people don't think is possible but you need to do on things like Astons and many vintage cars. And also panel fabrication. When the crowds hear us begin to start beating those panels into shape, they come flocking."
DIY restoration is hugely popular. Last year the Restoration Theatre drew huge crowds, and Leeds College's courses are already oversubscribed for next year. But having worked on old cars, and suffered the consequences, I cannot believe there are still people willing to put themselves through this kind of self-inflicted torture, particularly because, these days, classic cars are not worth nearly as much as they once were.
I asked Will Holman, editor of the restorer's bible, Practical Classics magazine, why he thought people still did it. "There is no logical answer, particularly when you are talking about cheap, everyday cars such as the Morris Minor. At least if you spend £10,000 restoring an E-Type it will be worth more than twice that. A Minor or a Mini will never be worth much. But luckily for us, that doesn't seem to stop them.
"There are some people, our readers mainly, who, when they see a rusty old car some undergo some strange psychological reaction and are impelled to restore it." His magazines' 70,000 readers testify to their enthusiasm; Practical Classics is the best-selling classic car magazine in the UK.
"It does require massive commitment," Mr Coman says. "A lot of people get into a restoration not really knowing enough about it, and my advice is to get to know people at the relevant club; they will give you all the advice and contacts you need. The other advice is to have patience. Many times, I have seen people fly in and rip a car to pieces without any idea of how to put it together again.
"Mostly, it will end up costing you more money than the car is worth, especially if you factor in your time, but there is nothing as satisfying as knowing you have rebuilt your car yourself. And we get a lot of people restoring cars with sentimental value, cars their dads or grandads owned, and you can't put a price on that."
Given the right equipment (£400 to £500 should set you up for welding and mechanical work), a reasonably spacious garage (with power supply) and the time, Mr Coman claims much is achievable at home. But he does advise leaving painting to the professionals. "You can do the preparation, but modern two-pack paints are poisonous. You can still use cellulose, but you will still have to buy a compressor and spray gun and you will have to work hard to get the similar results to a pro's."
Obviously, some cars are easier to restore. Old British stuff, such as Morris Minors and MGBs are good starters because every part is available new and they are Meccano-simple. Equally obviously, there are some cars you should not consider working on at home: anything with a V12, Italian exotica, or one-off, coach-built cars where you will have to fabricate parts from scratch. Another simple rule is that the bigger the car, longer it will take. That is easy to overlook when you chance upon a cheap MkII Jag in Autotrader, but most times an E-type will be cheaper and quicker to restore simply because there is less of it.
Mr Holman says a recent trend among restorers has been to modernise classics with new engines or improved brakes. In the late Eighties and early Nineties, restorers were obsessed by originality; these days they want to be able to use the cars.
That may make the cars more relevant, but it does not help restoration. Mr Holman says: "I restored an MGB. It took me two years working in my spare time and it was one big horror story. I certainly would never do it again. And it got nicked six months after I finished it." He is clearly still scarred by the experience.
If you are still tempted to do up an old car, a good start would be to take yourself along to the NEC next weekend and get a feel for what is involved. But my main advice is this: imagine the most severe endurance test, assume everything will go wrong, and that it will cost you twice, perhaps three times your budget and, when it is finished, if you have done a good job you will be too scared to drive it anywhere. Still tempted? Then I wish you well. Your country needs you.