The Jolly Christmas Postman is that rarest of things: A sequel, and a Christmas spin-off of a bona fide classic that turns out to be better than the original.

We follow the Jolly Postman (him again!) as he slip slides his way around Banbury Cross with an even more interesting load, packed full of cards, games and even an entire annual for one lucky residents of Toytown.

I wrote the other day about book apps, and how some of them needed to work a bit harder with their interactivity. Well developers could do a lot worse than to look at the work of the Ahlbergs, who with the Jolly Postman devised a deceptively simple format, that allows the reader to dive as deep as they want into the fairy tale world within.

Even more so than the original, the Jolly Christmas Postman is packed full of references, not just to the fairy tale characters but to itself. The first delivery is a Christmas card from Goldilocks to the four bears (an even babier bear has arrived), featuring a scene in Santa's workshop. We return to this location at the end when the postman gets lost in the snow and stumbles on FC's secret hideout. This is metafiction for beginners.

The Jolly Christmas Postman is a book of such generosity it's almost impossible to pick a favourite bit – though we're still playing Red Riding Hood's 'Get out of Woods' game, a present from Mr Wolf, in which you must negotiate your way past dozens of fairy tale traps and in-jokes.

If the Royal Mail are stuck for a series of Christmas stamps one year, they could do worse than to lift some of Janet Ahlberg's designs. There's the lion and the unicorn enjoying some Christmas cheer, Old King Cole even merrier than usual and Georgie Porgy using some mistletoe as an excuse to make yet more girls cry. Though I wonder what currency the 'u' belngs to?

Most spectacular though is the final envelope, especially for the Jolly Postman. Inside is a brilliant concertina card filled with yet more characters laden with gifts for everyone's favourite postal worker.

And if you want a little something extra in your stocking this year, then you could check out the Ahlbergs other Christmas book Cops and Robbers, or get the third book in the series – The Jolly Pocket Postman, which comes complete with magnifying glass. It's out of print, but I found a reasonably priced copy on eBay the other day- fingers crossed our postman isn't quite so sociable as the Jolly Postman and it gets here before the 25th.