I climbed the boarding ladder and entered the fuselage to find a flying office complete with all modern conveniences, most of them built-in. There were two desks, one with an electronic calculator and a recording machine, the other fitted with a typewriter, another tape recorder and a photocopier. I guessed that was Mrs Forsyth’s post. I opened a filing cabinet nearby; it was empty.

I moved aft and opened a door in a bulkhead. There was a corridor leading to the tail. I went along it and found myself in the galley, gleaming in stainless steel. I checked a cupboard at random and found what would have been a well-stocked cocktail cabinet had there been any bottles in it. Of course, if the aircraft had been due to go back to the manufacturers, the booze would have been tactfully removed.

The galley was spotless but there was not a scrap of food in it. Even the refrigerator was empty. I pulled down a flap and found myself looking into a microwave oven. After another glance around I decided there wasn’t anything for me here so I went forward again along the corridor.

There was a door on the starboard side which led into a sleeping cabin with accommodation for two. The beds were narrow but comfortable, as I found by testing, and they were made up ready for use. I slid open a wardrobe door and found three suits in various weights of cloth. When I checked the pockets I found nothing, not even a shred of lint. Whoever valeted Salton knew their job.

I drew a blank in the dressing table too. Neatly folded double-cuff shirts, underwear, ties, shoes, socks and nothing much else. All clean and tidy. But there was something missing and I couldn’t put my finger on what it was.

When I got back to the main cabin, Haslam was climbing aboard. ‘What do you think of it?’ he asked.

‘Where’s the ticker tape and the teletype?’ I asked jokingly.

He grinned. ‘It wasn’t for the want of trying.’

Something clicked. ‘There’s something else missing,’ I said. ‘There are shirts back there but no cufflinks; ties but no tiepins.’

‘Mr Salton’s personal jewellery is kept in the safe,’ said Haslam.

‘A safe? I’d like to see inside that. Can you open it?’ He hesitated, so I said, ‘It’s all right, you won’t get into trouble. And you can breathe down my neck.’

The safe was well hidden under the floor. It had a good combination lock and if you’d wanted to extract the whole contraption you’d have had to take the plane apart to do it. Haslam opened it and stood aside. I said, ‘How come you have the combination?’