'Beautiful.'

'We requisitioned it from the fantasy division of the Well of Lost Plots. It's a complete world in itself, written for a sword and sorcery novel entitled The Sword of the Zenobians. Beyond the mountains are icy wastes, deep fjords and relics of long-forgotten civilisations, castles, that sort of stuff. It was auctioned off when the book was abandoned. There were no characters or events written in, which was a shame – considering the work he did on the world itself, this might have been a bestseller. Still, the Outland's loss is our gain. We use it to keep grammasites and other weird beasts who for one reason or another can't live safely within their own books.'

'Sanctuary?'

'Yes – and also for study and containment – hence the password.'

'There seem to be an awful lot of rabbits,' I observed, looking around.

'Ah, yes,' replied Perkins, crossing an arched stone bridge that spanned the small stream, 'we never did get the lid on reproduction within Watership Down — if left to their own devices, the book would be so full of dandelion-munching lagomorphs that every other word would be "rabbit" within a year. Still, Lennie enjoys it here when he has some time off.'

We walked up a path towards a ruined castle. Grass covered the mounds of masonry that had collapsed from the curtain wall, and the wood of the drawbridge had rotted and fallen into a moat now dry and full of brambles. Above us, what appeared to be ravens circled the highest of the remaining towers.

'Not birds,' said Perkins, handing me a pair of binoculars. 'Have a look.'

I peered up at the circling creatures who were soaring on large wings of stretched skin.

'Parenthiums?'

'Very good. I have six breeding pairs here – purely for research, I hasten to add. Most books can easily support forty or so with no ill effects – it's just when the numbers get out of hand that we have to take action. A swarm of grammasites can be pretty devastating.'

'I know,' I replied, 'I was almost—'

'Watch out!'

He pushed me aside as a lump of excrement splattered on to the ground near where I had been standing. I looked up at the battlements and saw a man-beast covered in coarse dark hair who glared down at us and made a strangled cry in the back of his throat.

'Yahoos,' explained Perkins with disdain. 'They're not terribly well behaved and quite beyond training.'

'From Gulliver's Travels'?'

'Bingo. When truly original works like Jonathan Swift's are made into new books characters are often duplicated for evaluation and consultative purposes. Characters can be retrained but creatures usually end up here. Yahoos are not exactly a favourite of mine but they're harmless enough, so the best thing to do is ignore them.'

We walked quickly under the keep to avoid any other possible missiles and entered the inner bailey, where a pair of centaurs were grazing peacefully. They looked up at us, smiled, waved and carried on eating. I noticed that one of them was listening to a Walkman.