Asterix is on his 31st adventure

Its their joint birthday - no, we don't find out how old they are - and their parents give them weapons, which turn out to have been stolen from Caesar's enemy, the consul Pompey.

An actress is despatched to the Gaulish village disguised as everyone's favourite character from Asterix the Legionary, the beautiful Panacea, to charm the weapons back into Roman hands.

From then on the usual trouble ensues. Not only does the real Panacea make a guest appearance, we get all the villagers including Cacofonix the tone-deaf bard, the obligatory brush with the sinking pirates, and a finale from Julius Caesar himself - usually the mark of the best Asterix tales.

Also back in harness are devilishly witty translation duo, Anthea Bell and Derek Hockridge.

Potion

But there a few things that jar with the Asterix books of old.

The usually wily Asterix is for once as far behind the action as slow-witted Obelix, as he squirms like a teenager in front of his mother and is given a potion that makes him jump like a flea for a rather pointless few pages.

The story attempts the usual delicate twist of sub-plots as it moves towards its conclusion, but doesn't maintain momentum, and only succeeds in chopping and changing between scenes like a minor Pulp Fiction copy.

Asterix purists maintain that Albert Uderzo, the illustrator, should have stopped when his partner Rene Goscinny died, after Asterix and the Belgians.

Later books like Son of Asterix lose the edge in terms of wit, characterisation and plot, and sadly this is no exception.

However, this is one of the better of the later crop, thanks to its reliance on tried and tested characters and formulas - and the drawings, which are as much of a delight as they have always been (Asterix and Obelix's parents in particular are imagined well).

Like the purists, in theory I'd like to see Uderzo hang up his pen in deference to his old partner - but like the millions of other readers out there, the bottom line is I just can't resist a new Asterix.