He smiled and Agla returned it, knowing that a visit to Hólmsheiði was always an experience. First the weapons search, then the X-ray, occasionally the sniffer dog and finally the glass cage.

‘The first two visits are always behind glass,’ Agla explained. Not that she needed to; this man was hardly likely to become a regular visitor.

‘As we don’t have a great deal of time, I’ll get straight to the point,’ he said. ‘I represent a major drinks manufacturer and I have an offer to make.’

He stood up and held his business card up to the glass. She could see a little picture of him in one corner, under the company’s logo. Agla raised an eyebrow. International companies didn’t make a habit of searching out convicts in Icelandic prisons to offer them work. She pointed to her throat under her roll-neck sweater.

‘I’m sorry, but I have a sore throat. Could you explain?’

‘Of course,’ George laughed and sat down again. ‘This may sound strange, but we’re interested in certain connections that you may have.’ He took a slim plastic folder from the stack of papers and held it up to the glass as he had the card. ‘On this first page the graph shows the world market price for aluminium over the last few years.’

Agla glanced at it. The line showed a gradually increasing price.

‘The next page shows what my company has had to pay for aluminium for its cans over the same period.’

He pressed this against the glass and Agla compared the two graphs.

‘You’re paying way over the market price,’ she said.

‘That’s right,’ George agreed. ‘The problem is that there’s no aluminium to be had at the world market price, but there’s plenty on the open market, which is where we’ve had to buy it these last few years. We’ve had no choice.’

‘I’m not familiar with the metals business, so you’ll have to tell me where this is going,’ she whispered, forgetting her surroundings for the first time in longer than she could remember, and without even thinking to ask what it was that this man wanted from her. George leaned forwards, lowering his voice, as if he thought they were having a confidential conversation here in the Hólmsheiði prison’s glass cage.

‘The situation is this,’ he said. ‘There are two aluminium markets; registered and unregistered. LME, the London Metals Exchange, handles all the business with registered aluminium worldwide, and it sets a market price based on production volumes. But they don’t register all aluminium production, as part of it is sold on the open market, outside the system. Normally large buyers, as we are, don’t buy on the open market as there’s enough available on the registered world market. But over the last three years there has been practically no registered aluminium available, so the price of aluminium on the unregistered, open market has been shooting up.’

‘I assume that you or your company have complained to LME?’ Agla said.