The viewpoint character of Piggies is Ben, an ordinary young man of indeterminate age living an ordinary life. Then one day, without understanding how or why, he finds himself in a parallel world. Things here are very similar, there are just a few subtle variations. Some of the street names have changed. There are different shops. Oh yes - and all the people are vampires.

The theme of being an outsider and not fitting in with a hostile world is a common one for young adult books, however it's rarely taken this far. In this world of vampires Ben's family does not exist. He is alone with no way of getting home. He is in big trouble.

At first, Ben refuses to believe - refuses to use the "V" word. However as he sees more and more of the vampire way of life he finds himself reluctantly accepting the truth.

After a narrow escape from the vampires, Ben manages to meet up with a group of "ferals" - ordinary humans who don't drink blood. These people neither believe nor trust him and are far from helpful. Then he makes friends with a young vampire girl who lives on a farm. Things seem to be looking up.

The vampires in Piggies are not the stereotypes of film, they don't wear capes and run screaming from a clove of garlic. They're just ordinary people who happen to drink each other's blood. Gifford has created a very believable world where vampirism is the norm. As a result commonplace activities such as (to use an old-fashioned but appropriate term) "necking" suddenly become very different.

The casualness with which the vampires treat their - to them normal - lifestyle makes it all the more horrific. For me one of the most disturbing images was that of a young toddler suckling at its mother's... neck.

The marketing blurb says "And why is the book called Piggies? That's the worst horror of all." In fact any experienced reader of the genre will have spotted this coming a long way off. That said it is still a very, very nasty concept memorably executed.

As I said, this is a "young adult" book and the writing is kept simple. That's fine by me. One reason I enjoy books like this is that the author can concentrate on telling a story rather than trying to impress us with how clever he is. The writing won't be winning any literary prizes and I for one don't care. Though at the risk of seeming picky I must say that there were too many exclamation marks for my taste!

Many good books end badly. The last sentence of Piggies is perfect. It makes you shudder when you first read it. Then you do a double take as you realise the full horrific implications.

Perhaps the only real flaw with this book is that it is very short, I'd guess less than 40,000 words. If young people can manage Philip Pullman then they can manage a longer novel than this. I for one wanted more.

Gifford says he had great fun writing Piggies. On the basis of that I can't decide whether I want to meet the man for a drink or run away from him.