‘Yes. It’s always possible to exchange information if people want to badly enough.’ Alexej faced me. ‘It looks anonymous and a lot of these people think they can’t be traced. But every click can be monitored. And if they’re targeting kids, it could be mine one day.’ He pointed at the photograph frame on his desk of his wife and two children. ‘I intend to make sure that doesn’t happen.’

Alexej’s computer dinged.

‘Here we go,’ he said, ‘s10s has just posted. There’s another flash mob in London a week from today.’ He clicked into the ‘sign up here’ screen and entered the details for our dummy account, including the Gmail address and mobile phone number that Alexej had set up. Immediately, his Gmail account issued a message notification. ‘Bingo.’

‘Let’s make our voices heard. Working class areas of London are becoming the domain of the privileged. Join next week’s protest. Let’s bring dance to the streets of Limehouse and show the men in suits, the non-dom wankers and oligarchs that London doesn’t belong to them. We don’t want plush apartments, gastro-pubs and mindfulness classes. We want libraries, community centres and proper pubs. Most importantly, we want affordable housing.’

Underneath the post, there was a question.

mac: was last one invlvd with fire?

Alexej quickly screenshot mac’s question in case it got deleted, and clicked on the user’s profile. The forum offered the option to send private messages. Alexej typed one to mac: ‘u go to that one m8? proper scary.’

‘That’s enough for today.’ He logged out. ‘The analysts will be monitoring the forum. Too much activity looks suspicious.’

I checked the office clock. The press conference was in twenty minutes. I needed to decide how to phrase things to get the public on board.

Dan, 2.30 p.m.

Dan, 2.30 p.m.

Dan switched on the plasma screen in the office. ‘Here we go, team. Grab your popcorn. She’s on.’

‘ . . . am Suzanne Innes from the BBC,’ said the smiley reporter, ‘and we are live from Limehouse Police Station where there are developments on the recent arson investigation in East London. I’m here with Detective Inspector Maya Rahman from the Metropolitan Police who is about to release a statement.’