This was our world. Officially we were the Government Communication and Data Specialisation Branch used by MI5 and MI6 for specialist data analysis. Unofficially we went by the catchier Platform Eight and were a covert division tasked solely with missions that left no paper trail and no target alive.

We were Rats.

We scuttled around underground doing the unpalatable work necessary to keep everyone in Britain safe.

We were the Security Services’ dirty little secret.

I ran my hand against the concrete wall as I walked towards my meeting room. The division was a hive of activity. There were people hurrying up and down the corridors. Phones ringing. Shouts from office to office. Around sixty people work out of Platform Eight. Only half were Rats, the rest were Tech Support or working in departments like Surveillance, Special Projects and Research and Development. We may all have different skillsets, differing motivations, but all of us who worked at Eight shared the unfaltering belief that what we were doing was vital to national – and international – security. Sanctioned assassinations for the greater good. Saving lives by taking lives.

This was our final morning before a full lockdown. Unit leaders were calling in all Rats abroad or undercover.

Platform Eight was on high alert and we needed everyone in our network to be told.

Throughout London buskers were singing their hearts out. Today certain carefully positioned performers were singing songs specially chosen by us. Songs that had a special meaning to our undercover operatives.

In certain spots around town new graffiti would be appearing on key street corners. The homeless begging in specific alleyways would be holding signs in red.

In the days where electronic correspondence was monitored and could no longer be trusted we relied on a wide network of more simple forms of communication.

Everything usually ignored we used to our advantage.

The public – or the Sheep, as we liked to call them – wouldn’t notice these tweaks. These little changes. But all our people would know the symbols, the signs, the lyrics.

Run. Watch out. You’re compromised. This was what London was screaming to our operatives, to our informants.

We had got to Agent Black in time. The others might not be so lucky. There was a Snake in our midst and no one was safe. Slithering around alongside us, using their inside knowledge to hurt us above ground. None of us would be safe until this traitor was found. Until they were eliminated.

As I walked past an open office door I heard, ‘I’m worried. She hasn’t liked my latest photo on Instagram and I know she’s been on it this morning as she liked a photo of a dog walking in snow boots.’