‘Just an orange juice for me,’ she said, sitting down opposite him without removing her coat. ‘I never touch alcohol when I’m on an assignment.’

‘Very sensible of you,’ Slack said.

As Danny went off to the bar, Slack studied the woman who had come all the way from Mexico. Her eyes were the colour of dark chocolate and there was no emotion in them. In fact they quite unnerved him.

‘How was the journey?’ he asked.

‘Very pleasant. But then it usually is when one travels first class.’

‘And is the hotel to your liking?’

She shrugged. ‘Not really. It’s cheap and cheerful, but that’s OK because I understand it was chosen for its location. And anyway I’m not here on vacation.’

‘That’s true enough,’ Slack said. ‘And can I take it that your boss made you aware of how unusual this job is?’

‘It’s not that unusual, Mr Slack. I’ve taken out plenty of police officers over the years. Once I killed three in a single day and in different locations. I’m not in the least bit intimidated by the scale of this assignment.’

Slack was impressed. He could see now why Carlos Cruz had sent her and why she was so highly rated. She had the one essential attribute of all successful contract killers; she was not troubled by the conventional standards of morality.

Danny came back to the table with their drinks and Slack was struck by a jarring thought. To the other customers they no doubt looked like normal people, friends enjoying an evening out. But in reality they were the opposite of normal. Between them they had carried out scores of abhorrent crimes and were planning to commit many more.

Rosa suggested they steer clear of small talk and get straight down to business. So Slack told her about the organised crime task force and the text messages that had been sent to the detectives and their immediate family members.

Rosa raised her brow. ‘And do you really think that killing some detectives will stop the rest of them coming after you?’

He grinned. ‘Not at all. But that’s not why I’m doing it. This is just the opening salvo in a war I’ve declared against London’s police. I want to start by making them think it’s just about the task force. That’ll confuse and unsettle them before the real fun begins.’

At this point he took a mobile phone and a buff-coloured envelope from his pocket and handed them to her.