They spent the afternoon huddled around Abu Mujahid’s laptop. He connected it to a pay-as-you-go mobile phone and opened up the Street View map application, and he talked each of them through the routes they would be taking and the vantage points he had chosen for them.

Each of the men spent half an hour tracing their routes, familiarising themselves with the locations where they would be standing. By the end, Asad could plot the route with his eyes closed.

That evening, they gathered after prayers. Abu Mujahid sat in the centre, his face lit from below by flickering candlelight. The others watched, their eyes shining, basking in the glow of their leader.

‘The Quran is clear that jihad is justified to defend ourselves, to protect the freedom of our brothers, to protect our brothers from oppression and to make our faith stronger,’ Abu Mujahid told them. ‘Do not let the unbelievers fool you. They have declared war. To those against whom war is made, permission is given, because they are wronged.’

Asad went to bed early that night. The others were talking in the sitting room, listening to Abu Mujahid’s war stories, discussing the attack. Saleem’s voice was the loudest. He seemed to have no doubts, no uncertainties, just adrenaline-fuelled excitement.

Asad lay in the semi-blackness, a patch of light from the hallway shining through the glass panel over his door. Could he go through with this in three days? Did he have the strength that Muhid and Saleem shared? He prayed silently, lying on his front, eyes closed. He missed his family, his younger sister Aisha. What was his mother doing right now? Her life would never be the same. And when he opened his eyes, tears fell down his cheeks and splashed onto his pillow and he knew he loved Allah and would submit to Allah’s will. He would sacrifice his family, his friends and his life for Allah’s noble cause. For Paradise.

DAY 16

Thursday

Stonebridge, North West London

Asad was lying on his bed reading a densely written book on martyrdom and struggling to concentrate, and mostly thinking about Saturday, when Mirza entered.

‘What’s up, Tanvir?’ asked Asad, resting the book gently on the bedside table.

‘I need to go out for a bit, Omar.’ Mirza’s voice was quiet.

Asad sat up. ‘What you talking about, bro? You know what Abu Mujahid said. You mad?’

‘I need some fresh air. It’s too crowded…’

‘You’re not serious? You know you can’t.’

‘We’ve been cooped up for days. I’m going crazy, man.’

‘You know you can’t,’ Asad repeated. ‘Go out on the balcony if you need air.’

Mirza shook his head and pulled at his beard with his left hand. ‘Abu Mujahid won’t know. He’s gone out. I’ll just be a few minutes. I’ll knock quietly and you let me in.’

He walked out. Asad heard the front door to the flat open and close. He tried to read again, but gave up and turned on the TV. He flicked through the stations, and ended up on the news channel. The lead story was a new call from the Met’s head of counter terrorism for public vigilance.