‘Sartona. He obviously wanted me to think it’s Faulkner’s new alias, but I doubt it will be the name on his passport when he decides the time has come to make a break for it.’

‘Well done, choirboy, but I’m about to trump your ace.’

William couldn’t help smiling at the thought that Ross was one of the few people on the force who still dared to call him choirboy – to his face. He closed his notebook, sat back and listened.

‘While you were having a kip in the van and I was chasing Faulkner down the corridor, he slowed down to look at his watch. What criminal, I asked myself, checks the time when he’s being chased by a copper? When he touched the watch, the face lit up.’

‘So what’s the answer to your rhetorical question, Inspector?’

‘He already knew his study door was unlocked, because that was all part of his escape plan should the police ever turn up.’

‘And where does a wristwatch that lights up fit in with your “Rossonian” theory?’

‘First, ask yourself why there’s no handle or lock on the door of the safe.’

‘What’s your conclusion?’

‘It wasn’t a watch, but the key to opening the heavy metal door. All he needed to do when the face lit up was to enter a code and then the door would open.’

‘That would explain how he managed to disappear into thin air but was still able to call the butler moments later.’

‘And if you’re interested,’ continued Ross, ‘I can tell you the name of the company that made that door.’

‘NP,’ said William, still in the game. ‘The letters that were engraved in the bottom left-hand corner.’

‘Not bad, choirboy, but do you know what NP stands for?’

‘No, but I have a feeling you’re about to tell me.’

‘Nosey Parker. Colonel Parker is the one man who can tell us how to open that door.’

‘But you’ve only got a week to go before you leave the force.’

‘Then I may have to postpone my retirement for a little longer if I’m going to prove my theory is right.’

‘Who needs an ex-copper who’s going to work for a holiday company run by two complete lunatics?’

‘You do,’ said Ross, producing a small tin box from an inside jacket pocket. He flicked it open to reveal the plastic mould of a key.

‘Faulkner’s study door?’

‘If I’d taken the key,’ said Ross, ‘he would have had the lock changed before we’d reached the airport.’

‘Anything else?’

‘Yes,’ said Ross, producing his miniature video camera. ‘I’ve recorded the only safe route through the forest to the front door. So you can’t survive without me.’

William admitted defeat and shook hands with his partner as a stewardess leant over and handed each of them a plastic tray of dry rice and heated-up beef, with a sachet of brown sauce.

‘Anything else?’ asked William.

‘Yes,’ said Ross. ‘I’d prefer to be sitting up front in first class next to Christ.’