Silva sighed. ‘Dad, I know you’re trying to do the right thing, but surely this isn’t the way. Please tell me you’re not getting involved. Please tell me you’ll drop this.’

‘I’ll do what I want. It was good to see you the other day, Rebecca. We must do it again sometime.’

Her father hung up and Silva remained sitting on the wall for a long time. When a neighbour came out from the next-door property and asked if she was OK, she stood, shrugged and walked off down the street to deliver the rest of the mail.

They were back in the office. Pension Man and the Boy Wonder. Two superheroes fighting a global terrorist network with Taher at its centre and the world on the brink of disaster. Something like that anyway.

Over the past couple of days Holm had put a lot of thought into their next steps. Did they ignore the mysterious Twitter account and the clue that led to Ben Western? Holm was minded to do so. It was possible the information was bogus or the whole thing was a set-up designed to push him in the wrong direction. On the other hand the execution-style murder of Western – which it appeared to be – was rare enough to warrant another look. On a hunch Holm called a friend he’d once worked with in Special Branch. Special Branch was now renamed and reconfigured as Counter Terrorism Command, but his friend was still hanging in there.

Bob Longworth and Holm went way back, even further than Holm and Palmer. They’d graduated from Hendon Police College at the same time and risen through the ranks. A few years ago, Holm had tried to persuade Longworth to move to JTAC, but he’d declined.

‘You know me, Stephen,’ he’d said. ‘Paperwork makes my head hurt. Pointless and expensive paperwork doubly so. I try and do as little of it as possible.’

‘Bob,’ Holm said when Longworth picked up. ‘A favour. Off the record, at least off my record. Can you do that for me?’

‘Depends entirely on what it is,’ Longworth answered.

An hour later Holm hand-delivered a note to Longworth at Scotland Yard and promised him payback in the form of a lunch. Longworth glanced down at the note.

‘Why can’t you route this through official channels?’ he said.

‘I’ve been sidelined,’ Holm said. ‘After what happened in Tunisia I’m supposed to stay well clear of anything in this area.’

‘I’d heard something on the grapevine but didn’t believe it.’ Longworth looked pained. ‘Stephen Holm investigating bunny huggers?’

‘Now you can see why I don’t want Huxtable to know about this.’ Holm pointed at the piece of paper. ‘She’ll have my bollocks in a glass jar on her desk if she finds out.’

‘If she finds out I helped you go behind her back then mine’ll probably be floating in there too.’