The light went green and a trickle of cars filtered through onto Charing Cross Road. No wonder this city grinds to a halt so easily when people are so bloody slow to react to a green light!

He found Georgie’s number and rang that. Unlike his previous call, this was answered with considerable enthusiasm.

‘Hi, Charlie!’

‘Georgie? Are you dressed?’ He hadn’t meant that to sound sleazy but it came out wrong and he heard a moment’s hesitation at the other end of the line. ‘I mean, are you up?’

‘Yes! Been up for hours. I don’t sleep well.’

‘Me neither. Grab your coat – I’ll be outside your flat in a few minutes. We’re going for a ride.’

*

Georgie had been partially truthful. She was up but she had still been sitting in bed reading when Charlie had called. What occurred next was a furious transformation out of a pair of Charlie Brown pyjamas (a present from her mum she could not bear to part with) into a pair of jeans, white top and a brown body warmer. She grabbed her phone and stuffed a purse into one of the body warmer’s pockets. According to Li, it was a hideous garment that made her look like Dora the Explorer but its redeeming feature was an array of deep pockets which meant she didn’t need to carry a bag.

She was standing outside her flat waiting for Charlie in six minutes flat. The Volvo pulled up onto the kerb and she hopped in the passenger seat; a wave of heat from the inside of the car hit her. When she closed the door, she felt suffocated by it.

‘It’s like a sauna in here,’ she said.

‘The heating’s broken,’ Charlie explained. ‘Just open the window a bit.’

Georgie found that the window was operated by a crank mechanism below the door handle.

‘Why don’t you use the other car?’ she asked, poking her head out the window to inhale fresh air. ‘You have an Aston Martin.’

‘This was William’s car. He could have bought whatever he wanted but he preferred this for some reason I’ll never understand. I promised him I’d look after it until he gets out so I keep it running so it doesn’t rot in a garage somewhere.’

Georgie looked at him uncertainly. ‘William isn’t likely to get out soon, is he?’

Priest laughed. ‘Doctor William Priest is one of the most prolific serial killers London has seen since Jack the Ripper. He’s also clinically insane. He’s never getting out.’

‘Then why . . . ?’

‘Because I promised him I would.’