‘They’ve been charged,’ Tillottson said, ‘with theft. They won’t make a statement.’

Alleyn said to the young man: ‘I’m going to put questions to you. You’ve been taken into custody and found to be in possession of a jewel belonging to a lady into whose death we are inquiring. Driving licence?’ He looked at Tillotson who slightly nodded. The young man, sketching boredom and impertinence in equal parts, raised his eyebrows, dipped his fingers into a pocket and threw a licence on the table. He opened his mouth, accelerated his chewing and resumed his former pose.

The licence was made out in the name of Albert Bernard Smith and seemed to be in order. It gave an address in Soho.

‘This will be checked. The night before last,’ Alleyn said, ‘you were on the tow-path at Crossdyke alongside the Zodiac wearing those boots. You had parked your bicycle under a hedge on the left-hand side of the road above the lock. Later that night you were here at Ramsdyke. You arrived here, with a passenger. Not:’ he looked at the girl, ‘this lady. You carried your passenger—a dead weight—’ For two seconds the slightly prognathic jaw noticed by Dr Natouche, stopped champing. The girl suddenly re-crossed her legs.

‘—a dead weight,’ Alleyn repeated, ‘down to the weir. Her pyjamas caught on a briar. You did what you’d been instructed to do and then picked up your present companion and made off for Carlisle where you arrived yesterday in time to send a telegram to the Skipper of the Zodiac. It was signed Hay Rickerby-Carrick which is not much like Albert Bernard Smith. Having executed this commission you turned south and were picked up by the police at Pontefract.’

The young man yawned widely, displaying the wad of gum on his tongue. He stretched his arms. The girl gave a scary giggle and clapped her hand over her mouth.

‘You’ve been so busy,’ Alleyn said, ‘on your northern jaunt that you can’t have heard the news. The body has been found and the woman was murdered. I shall now repeat the usual warning which you’ve already had from Superintendent Tillottson. At the moment you are being held for theft.’

The young man, now very white about the side whiskers, heard the usual warning with a sneer that seemed to have come unstuck. The girl watched him.

‘Any statement?’

For the first time the young man spoke. His voice was strongly Cockney.

‘You can contact Mr C.D.E. Struthers,’ he said. ‘I’m not talking.’

Mr C.D.E. Struthers was an extremely adroit London solicitor whose practice was confined, profitably, to top-level experts in mayhem.

‘Really?’ Alleyn said. ‘And who’s going to pay for that?’

‘Mention my name.’

‘If I knew it, I would be delighted to do so. Good evening to you.’

When the couple had swaggered unconvincingly to the cells Tillottson said: ‘ “Smith” they may be, but not for my money.’

‘Ah,’ Fox agreed. ‘They’d have done the virtuous indignation stuff if they were.’