Satisfied with her appearance, she left the room, went downstairs, and exited the hotel.

The air outside was raw and she was glad to see that the street was heaving with traffic and pedestrians. She’d decided to strike at the tail end of the rush hour. She wanted to make it as hard as possible for the cops to spot her going to and from her victim’s house.

She knew that extreme caution was necessary in a city with over half a million surveillance cameras. She’d spotted plenty of them while checking out the various locations today and she’d try to avoid them where possible.

She walked briskly to the pub, which was only a couple of hundred yards from the hotel. She let herself into the garage at the rear and got to work.

The first thing she did was remove her coat and slip into the two-piece motorcycle suit. Then she picked up the pistol she’d chosen for the first hit and put it inside the jacket. Finally, she picked up the helmet and rolled the bike outside, locking the door behind her.

She wheeled the bike out onto the road and got on it. Before placing the helmet on her head she made a call using one of the burner phones that Slack had given to her. She’d put the number in earlier so that she wouldn’t have to memorise it.

It rang three times before being answered.

‘Hello.’

It was a woman’s voice and Rosa assumed it must be the victim’s wife.

‘Is Detective Inspector Prentiss there?’ she asked. ‘It’s the office here.’

‘He is but I’ll have to get him,’ the woman said. ‘Who shall I say is calling?’

Rosa abruptly ended the call, turned off the phone and dropped it on the ground where she smashed it beneath her trainer.

Then she put on the helmet and fired up the bike.

It was a relief to know that DI Dave Prentiss was at home. He would be her first victim and hopefully he’d be dead within the hour. That would give Rosa plenty of time to make a night of it in London’s famous West End.

With luck she might even get herself laid.

Dave Prentiss lived in a quiet street in Battersea, less than a mile from the hotel in Vauxhall.

He had just become a father, information gleaned from his wife’s most recent social media posts. Rosa therefore stopped on the way to the house to buy a bunch of flowers.

She’d also decided that if it was the wife who answered the door then she’d be the one to die. After all, the brief was to kill the detectives or the family members and loved ones whose names were on the list she’d been given.

She’d seen photos of both husband and wife so she wasn’t going to make a mistake.