There was a relieved cheer and a quick burst of applause from the audience. We do love drama, and I looked forward to the chats afterwards about whether Soldier John would be prepared to kill somebody during a lecture. My view would be . . . possibly.

‘I want you to imagine Dr Jones ’ere is a krik.’ Soldier John waved his arm up and down the full length of her body and Dr Jones smiled, doing jazz hands.

‘This is a great idea, John,’ said Dr Jones. ‘Because funnily enough, we saw some kriks today.’

‘I know,’ said Soldier John. ‘That’s why we’re thinking about how to kill ’em.’ He picked up a sharp shard of hard plastic. ‘Now, how to kill the fuggers. Your basic krik gets ’arder to kill the older it is, you see. When it’s first born, its shell is softer and it’s smaller, so it’s just the same as killing a ’uman. You just stab ’em in their vulnerable areas. Any questions?’

We looked at each other.

James stuck up his hand. ‘Erm . . . imagine that we’ve never killed a human before. How would you recommend best killing one?’

Soldier John looked at him as though he was a complete idiot. ‘You just stab them through the ’ead, or the ’eart. You can also slit their throat, or strangle them to cut off their air supply. I’ll do another lecture on killing ’umans one evening. A useful skill.’

‘Thanks,’ said James. ‘Yes. Useful.’

‘The impo’tant thing with a krik, though, is you’ve got a shell to get through before you can get to the vulnerable areas. So.’ Soldier John gave a flourish with the large shard of plastic. Standing behind Dr Jones, he pointed it at her head. ‘The best way to kill a young krik is by stabbing or cutting ’ere.’ He held the shard against the top of Dr Jones’s head. She gave a cheery smile. ‘You’ll need a lot of force, but it’s still easy. If you can’t kill ’em,’ he glanced sideways at James, ‘then at least try to wound them. Slice off one of the legs, so that they can’t chase after you.

‘Kriks that are older,’ he continued, ‘are a different matter. Very different.’ He shook his head and curled his lip, giving another long, dramatic pause for effect. ‘Older kriks are faster than ’umans, stronger than ’umans, and can only be killed with a knife if you’ve broken through their exoskeleton first. You don’t stand a chance of gettin’ through it without smashin’ it first. I recommend metal bars, or wooden planks.’