She’d been denied the chance to let her hair down in Acapulco, so she felt she deserved it now. She had already selected her next victim and carried out all the necessary research. So there was no need to spend the evening formulating a plan.

That first kill had been a breeze, but she anticipated that from now on things would get a little more difficult. She was OK with that, even welcomed the challenge, because there was only so much the cops could do to protect themselves.

In Mexico every police officer, journalist and judge knew they were potential targets of one or more of the cartels. Some went to extraordinary lengths to try to ensure they stayed safe. They hired armed bodyguards, moved house, cut themselves off from the rest of the world. But ninety-nine per cent of the time they still ended up dead.

Rosa had learned from experience that every line of defence could be breached. Usually it was down to human error or underestimating the guile of the assassin.

Rosa was proud of the fact that she had never failed an assignment, no matter how difficult it had appeared at the outset. She had a work ethic that put her peers to shame and would have made her an asset to any terrorist organisation.

Having spent so many years killing people she couldn’t imagine doing anything else for a living.

Before his death her father had started sharing all the hopes and dreams he’d had for his only child. But those memories had been distilled by the passage of time so she couldn’t remember what he wanted her to be.

Of one thing she was certain, though – that neither of her parents would have been proud of the fact that she had turned into a killing machine. And that she’d earned the dubious distinction of being rated as the best in the business.

An hour after leaving the hotel Rosa walked into a lively little nightclub in the heart of London’s West End.

The place was heaving with men and women who all seemed to be in their twenties and thirties. Some were gyrating on the dance floor while others were standing at the bar or sitting at little round tables. Rosa was delighted to see that a good many were by themselves. No doubt they were hoping to get lucky just as she was.

Back at the hotel she had replaced the navy polo sweater with a tight pink T-shirt and the black jeans with her favourite pair of designer ones.

She knew she looked a million dollars and so she wasn’t at all surprised that she drew so much attention as she walked purposefully up to the bar.

A couple of women smiled at her and she smiled back. One guy in a string vest and white arse-hugging shorts blew her a kiss and she returned the gesture.