William pushed his way through the swing doors, as Ross jumped into the back of the car, leaving the door open. William hadn’t even closed it before Danny accelerated away.

They shot out of the Yard, siren blaring. Danny drove straight through a red light on the corner of Victoria Street, causing several vehicles to throw on their brakes, followed by irate horns blaring.

‘Do we have the exact location?’ William asked, clinging to the seat in front of him.

‘Prince Albert Crescent,’ said Danny, as he sped past the Palace Theatre in the direction of Hyde Park Corner. Several vehicles eased across to their right and left, allowing the car in their rear-view mirror to continue on its journey uninterrupted.

William’s first thought was that the Fitzmolean was on Prince Albert Crescent. He tried to dismiss the idea from his mind. The radio buzzed, and William grabbed it. ‘Chief Inspector Warwick,’ he said.

‘Inspector Preston, sir. I’m the duty officer at West End Central. DS Roycroft has just called to say you wanted to be briefed immediately.’

‘Correct,’ said William, not wasting a word.

‘A young woman has had her throat slit in Prince Albert Crescent,’ said Preston. ‘It looks to me as if it was premeditated, and the killer knew his victim.’

‘Any idea of her identity?’

‘No, sir. A passer-by saw a car draw up by her side and a heavily built man wearing a stocking mask jumped out and slashed her across the face several times before finally slitting her throat. He then got back into the car which took off at high speed. It was all over in a matter of seconds.’

‘Did anyone get the vehicle reg?’

‘DS Adaja asked me the same question, but all we know is that the witness was pretty sure it was a black BMW.’

‘Can you give me a description of the woman?’

‘That’s not easy, sir. She’s been badly disfigured.’

‘Skin colour, age?’

‘Caucasian, I’d guess early thirties.’

William could hear his heart thumping.

‘Weapon?’ asked William, as Danny continued to weave his way in and out of the traffic.

‘A small, thin knife with a serrated edge. He left it sticking out of her throat. It was almost as if he wanted us to know who’d done it.’

‘He did,’ said William, as he picked up the sound of another siren in the distance. ‘Don’t allow the medics anywhere near the body before I get there.’

‘Understood, sir,’ he said.

As Danny shot past Harrods, pedestrians turned to stare, and as they got nearer, William offered up a silent prayer, trying to convince himself he was overreacting. Eventually, Danny touched the brakes lightly and swung left into Prince Albert Crescent, the speedometer still touching fifty. They couldn’t miss the large police presence a couple of hundred yards ahead of them. A crowd of onlookers were gawping from the pavement on the opposite side of the road.

Danny screeched to a halt just feet away from the blue and white tape that surrounded the crime scene.