Peterson coughed loudly into his napkin, a less than subtle warning that Knox should check his tone. Knox ignored him.

‘Would you like my report, sir?’ he asked.

‘Report?’

‘Into Bianchi and Moretti.’

‘Oh, yes.’ Manning turned to his two young acolytes. ‘Phillips, Harris, if you could excuse us for a moment.’

‘No need,’ Peterson said, placing his napkin on the table and shuffling out of the booth. ‘You can give it to me, outside.’

‘I really think the director general should hear it,’ Knox replied.

‘He will. Through me.’

Peterson guided Knox quickly out of the restaurant. Then, on the corner of Jermyn Street, asked him what exactly he thought he was playing at.

‘First buggering off to Cambridge and Holloway without approval, and now trying to make a scene in public. What the hell’s got into you?’

‘You sound stressed, Nicholas,’ Knox replied, his voice full of mock concern.

‘We’re in a period of transition,’ he replied. A political, neutral answer. ‘Everyone is feeling the strain.’

‘They look pretty relaxed to me.’ Knox pointed through the window at the three men still enjoying their lunch, Phillips and Harris hanging on to whatever anecdote Manning was telling them.

‘They haven’t spent all morning keeping the Spanish and Portuguese delegations from each other’s throats,’ Peterson said, somewhat less neutrally. ‘That thankless task fell to me.’

‘And I’m sure you put up a fight.’

Peterson let out a long sigh. ‘I don’t have time for this, Richard. What’s going on?’

‘I know why they were killed.’

‘So?’

It wasn’t the response Knox had expected.

‘You think that justifies talking to Manning like that?’ Peterson asked.

‘They weren’t just troublemakers. They’d worked out a way to replicate Pipistrelle.’

Concern suddenly flickered across Peterson’s face. He stepped closer to Knox.

‘You have proof?’ he asked, lowering his voice.

‘I have their equations. Their real equations.’

‘What the hell does that mean?’

‘Another set of papers. Hidden in their apartment, and not very well.’

Peterson glanced through the restaurant’s wide windows at Manning. Knox enjoyed imagining the cogs turning in his mind.

‘Your conclusion?’ he asked, when he turned back to face Knox.

‘Either they were hiding it from the person who killed them. Or they were hidden after they died, by someone who didn’t want me to see them.’

‘That sounds a little like putting the cart in front of the horse.’

‘Not if this whole thing is a set-up. They were behind a bookcase in the study, where Manning was waiting for us.’

Peterson sighed again, and took half a step back. ‘And that sounds more than a touch paranoid.’

‘Everyone’s a suspect,’ Knox replied, throwing Peterson’s line from the previous night back at him.

‘You seriously want me to believe the director general hid evidence in the middle of a crime scene and a whole team of investigators missed it?’