Ok, so we all know the correct, art-historical use of the word "cartoon" refers to some finely worked Old Master drawing, but how many of us ever think of cartoons like that? Cartoons are Tom and Jerry, Dennis the Menace, the page you turn to first in your newspaper, the characters in Viz. They're the appalling schoolgirls of St Trinians. They're Ralph Steadman, all those curiously unfunny jokes in 19th-century copies of Punch, or going back even further, the satirical sketches of James Gillray, which were so critical of the then Prince of Wales, the overweight, self-indulgent and thin-skinned George-IV-to-be, that the government of the day paid Gillray a pension to go away and draw no more. Britain invented the cartoon (not a lot of people know that), and now, at 35, Little Russell Street, two streets along from the British Museum, we have the Cartoon Museum – one of London's youngest and certainly one of its smallest museums.

One of the problems with cartoon humour is that it dates. Very few jokes hit that universal truth that makes them relevant, let alone still amusing. So if you are setting up a Cartoon Museum, to tell the history of the art-form as well as introduce its major practitioners, from the 18th-century to the present day, you have a lot of show-and-tell to manage, and that's a risk. This is one of the things that museums can get quite spectacularly wrong, but not so here. There are big didactic panels to place what you are looking at in context, there is an excellent overall timeline, and smaller captions by each cartoon to give you its individual history and importance and explain exactly what it the cartoonist was inspired or infuriated by; and all are written so well, and are so readable, and often so amusing, that the huge amount of information you're absorbing almost goes down without you noticing it. Until, you find yourself standing before an engraving by an artist you have never heard of (John Collier; 1708-86, in this case), feasting on his piled-up caricatures and wickedly accurate little figures, and thinking 'This is Breughel! Got it! Shakespeare's yokels! The English sense of humour! Of course we would have invented this!'

I mentioned that the museum must be one of London's smallest – well, so it is. You enter through the gift-shop, for a change (one small room, but one that will be seeing me again), and on the ground floor are two spaces – the first gives you an introduction to the history of the cartoon, the other of which is a temporary exhibition space, showing, when I visited, the work of Trog. These are the originals (cartoonists or their heirs are clearly admirably generous), complete with scratchings-out and Tippex and hand-scrawled punch-lines; not merely the printed versions in their pristine black-and-white. Upstairs there is an art studio, where you can learn the art of cartooning yourself, and then a display of characters and artworks from the Beano to the new classics of the graphic novels of today. For a baby-boomer, such as me, it's like meeting up again with some of your first and oldest friends – the Bash St Kids, the work of Posy Simmonds, the famous V for Vendetta. And of course there is the ever-wonderful, ever-inventive Viz. A tribute to Ralph Steadman is planned for later in the year.

Which brings us full-circle. The loopiness, the satire so funny that to your own shame you find yourself overlooking its viciousness, the wry indulgence yet cold-blooded anatomizing of human weakness, the same distillation and concentration of message, the same graphic punch and virtuoso line you see in the earliest examples displayed downstairs, are up here too. Which is of course the argument for setting up a museum in the first place. All these artworks still have meaning in isolation. But gathered together like this, they form a history. They tell a bigger, layered, more important story. And, at the Cartoon Museum, they will make you laugh out loud.

Cartoon MuseumErato reviews The Cartoon Museum in London.3