‘No you don’t,’ said Matthew. ‘Not any more. The artists who do well these days are precisely those who can’t paint. And as for sculpture, that’s very old-fashioned, Lou. Installations are the thing now.’ Matthew looked around the room. ‘Take your coffee machine, for example. That has two prices: the price you pay for it if you buy it in a kitchen equipment shop, and the price you’d get for it if you put it on a plinth in a gallery and labelled it Age of Steam or Chrome III.’

‘Oh yes?’

Matthew nodded. ‘Yes.’

‘So if I put it in your gallery I’d get a large price?’

‘No,’ said Matthew. ‘Not you. It would have to be put in by somebody who had been recognised by the cognoscenti as conferring artistic validity to the object. That would mean that you would have to be chosen by the people who create the market. If they chose you – if some big collector said Big Lou is eminently collectable – then that would confer that status upon you. You’d be anointed, so to speak. Thereafter anything you presented as art would be ipso facto art.’

Matthew drew breath. ‘And another thing. It couldn’t be my gallery because I can’t confer validity. It would have to be one of the galleries that are accepted as being the sort of place where coffee makers – or anything, for that matter – can be sold as art. I’m not in that line of apostolic succession, so to speak.’

Big Lou was thinking. ‘The Dutch tulip affair,’ she said. ‘I was reading a funny wee book about social hysteria – about how folk get things into their heads and go mad for a while. There was something about witchcraft.’

‘Moral panic,’ prompted Matthew.

‘Yes. That sort of thing. Didn’t the Dutch go mad about tulips back in the – when was it – 1600s? Didn’t they pay terrific prices for tulip bulbs? And these bulbs got more and more expensive and people fought to have the rarest ones they could get hold of. Sheer stupidity.’

‘Yes,’ said Matthew. ‘And then suddenly somebody said, “Hold on, it’s just tulip bulbs, and tulip bulbs aren’t really worth the price of a house.” ’

‘And everything collapsed. Yes. Do you think that people in the art business know about the tulip disaster?’

Matthew smiled. ‘I suspect that they know only too well. But the problem is, they can’t do anything but keep up the entire pretence and carry on buying these banal conceits because if they didn’t their collections would be worthless. Who would want to buy a shark in a tank of formaldehyde? Especially if the shark started to decay and fall to bits? You have to pretend that it’s still important, still worth keeping, because if you didn’t you’d lose millions of pounds.’