I have just completed one of the most difficult projects I have undertaken.

A book on cartooning. Odd that it should have been so hard given that I am a cartoonist and have been drawing professionally for over 25 years.

But it became one of those very personal endeavours that you agonise over getting right, fuss with endlessly and generally drive everyone around mad with. (I like ending sentences with prepositions.) One of the things I have been keen to emphasise in the book is that cartoons are not just for kids. Some of the best cartoons are done for kids (Quentin Blake, for example) but it is not some noddy deviant relative of real art, to be dismissed by grown ups the world over.

Cartoonists have brought down governments, undermined politicians, attacked dictators, annoyed major world religions, taunted tyrants and taken men to the moon. (I may have got carried away with the last one.) The point is, it is a valid art form with a strong tradition. If you don’t believe me, go visit the British Cartoon Museum in London.

Cartoonists, children’s illustrators and comic book artists are, in my opinion, hugely undervalued in this country.

Some produce work of far greater artistry than any of the contemporary Brit Art clowns.

Someone once asked me what I did for a living and retorted, “Cartoonist? That must be a nice little life.” I decided to ignore the patronising tone and asked what he did instead.

It turned out he was a manager in a city company and therefore astonishingly boring. Loads of money, no time, no life.

I therefore saw it as my duty to regaled him with some of the jobs I had done, the exciting and exotic clients I had worked for and the endless freedom and creativity my nice little life afforded me.

I have no idea if he saw the point but it felt good to me.

Cartooning is a brilliant way to earn a living. You get paid to make people laugh and you’re legitimately allowed to spend all day playing with ideas.

Sometimes you get to annoy politicians. (Although if you do, the chances are they will ask for the original artwork, which takes the edge off the sense of satisfaction you may feel.) I wouldn’t swap jobs for the world. It has brought me untold wealth, fast cars, glamorous women and a jet-setting lifestyle. (Some or all of the last sentence may be untrue.) Laughing keeps you healthy and helps you live longer: I recently interviewed American cartoonist Arnold Roth - 80 years old and determined to keep cartooning until nature intervenes (his words, not mine).

So my message at the end of the book, to any aspiring cartoonists: go out there, do your best work, draw what makes you laugh and hope it will also amuse your clients.

With luck you’ll never have to return to the day job.