When he drifted into the side of the canal below the wall of his own factory yard five minutes later, there was already a considerable disturbance in the vicinity of the furniture factory and a red glow stained the darkness, flames leaping into the night from the stack of burning crates.

He took a knife from his pocket and slashed the dinghy in several places, forcing out all air so that he was able to stuff it into the hold-all again, then he tossed it over the wall with the jerry can and followed them.

He left the can with a stack of similar ones on his way through the garage and returned to the tenth floor in the service lift. The moment he was safely inside his office, he reached for the ’phone and dialled his home. As before, the receiver was lifted instantly at the other end.

‘You’re late,’ Harriet said.

‘Sorry about that. I must be getting old.’

She chuckled. ‘That’ll be the day. Everything go off okay?’

‘Couldn’t be better. I won’t be home just yet, by the way. I want to finish the details on the vibrator modification in time for the staff conference tomorrow.’

‘How long will you be?’

‘Another couple of hours should do it.’

‘I’ll have some supper waiting.’

He replaced the receiver, went into the washroom, scrubbed the filth from his body and changed quickly. He had hardly returned to the other room when there was a knock on the door and George came in.

‘Hell of a fuss going on up the road, sir. Don’t know what it’s all about, but everybody seems to be there. Fire, police – the lot.’

‘Go and have a look if you like,’ Craig said.

‘Sure you don’t mind, sir?’

‘Not at all. I’d be interested to know what’s happening myself.’

He sat down at the drawing board and picked up his slide-rule and George went out quickly.

Miller and Grant stood by the ashes of the fire and surveyed the scene. The Fire Brigade had left, but the big black van that was known throughout the Department as the Studio was parked just inside the gates and the boys from Forensic were already getting to work on the truck.

‘So no one was around when the first car got here?’ Grant asked, for he had only just arrived on the scene and was seeking information.

‘That’s right, sir. Whoever was here must have cleared off pretty sharpish. Of course the fire was bound to attract attention.’

‘What about the truck?’

‘Hi-jacked two days ago on the A1 near Wetherby. Carrying a consignment of export Scotch to the London Docks. Valued at £30,000.’

Grant whistled softly. ‘That’s going to bring the county’s crime figures down a bit. And you say you didn’t recognize the informer’s voice?’ he added incredulously.

‘I’m afraid not.’