He turned and rapped on the inside of the roller shutter. It rattled up and some men I didn't recognise helped him down. One of them jumped up onto the tailgate and hauled it back down. I heard them lock it from the outside. And then I was alone, strapped to a bomb I'd helped make. In my mind's eye, my boss's "keep calm and carry on" mug had swum into my mental vision. Yeah, that could work.

I had nine minutes. Lord Khalil was wrong in one respect though - this bomb was so powerful that any DNA left of me would be in orbit, and everything for fifty metres would be carbonised. I had to think. THINK, dammit!

Zip ties.

I gave a heartfelt prayer of thanks to almighty Allah. Zip ties.

OK. Deep breath.

I wriggled about a bit to get traction. Yep. They'd tied me to a bit of rope too. Good. The trick was to get your arms up behind your back as far as possible and slam them down onto your butt, like some mad frog jump. I went for it. One. Nothing.

I wriggled more, to get purchase, and coiled my body. Here we go. Whack. Nothing.

For fuck's sake Riz, get a grip and do it right. I probably had eight minutes. Arms up as far as they go. I felt like an Olympic diver. DO IT. I slammed my arms down.

Pop. The ties snapped.

I fell to the floor of the van and laughed in relief. The ties on my feet were easier. I wriggled and struggled till they snapped.

OK. Now the bomb. I wobbled to my feet and looked at the pallets. The first thing you had to do was check for anti-handling devices. We hadn't built any in, and I couldn't see any alterations. Second thing to do was to remove the power supply. And there it was. The nine-volt battery. My hands hung over it. I gave the firing train one last look. In the movies there was always a big red digital timer or some mad beeping noise. Not in real life. In real life the bombs quietly ticked down to the bang.

I unplugged the battery. I looked at the mobile phone. The back had been removed and two wires soldered in. I pulled them away. Then, very gingerly, I reached in and extracted the TATP from the booster charge and laid it on the floor. The device had been made safe. Relatively safe.

Miraculously, they hadn't taken my watch ... or ... I checked my wallet. It even had money in it. Two twenty pound notes. I supposed they wanted as much of my stuff on me as possible. It was 10.14am. How could I get out of this van? I pulled on the shutter. Locked from outside. I looked up. Luck. This Luton had the semi-transparent skylight roof. With something sharp, I could cut through it. I looked at the bomb. There. The frame that attached it to the floor. It looked a bit like meccano. I yanked at it like a madman and eventually it gave way.

I climbed up onto the pallet of ANFO and sugar and steadied myself. Above me was the roof. I began stabbing at it. The whole time I was stabbing, the same thought was running through my brain. Stratford. Bombs. Two teams. I made a ragged hole. I stopped. The phone. I got back down and fetched the mobile, then hauled myself up and out onto the van roof into a bright sunny day. I tried the mobile. 999.

Fuck.

' No SIM card' .

The bastards had just been using it for a timer. Where the hell was I? I looked around. The van was parked in a square, outside a post office, nowhere I recognised. Right about now would be the time it would detonate. I looked for the position of the sun. It was high in the sky at ... 10.20? I was looking south. Suddenly on the horizon was a white flash. Several seconds later was a rumbling thud.

Oh God. The second bomb.

I had to move. I jumped down onto the cab roof dropped off of the side, landing heavily. I stumbled back and registered that they'd spraypainted "NHS" in big blue letters down the side. I ran into the post office. I grabbed the nearest person.

'Where am I?'

He looked at me blankly. The British curse. He didn't speak English. There was no time to mess around.

'What's this address? I'm police and I need to know!'

Everyone in the post office turned to look at me.

'You're in Welwyn mate.'

A chavvy looking bloke had spoken. There were several TVs on the walls tuned to BBC News, and they were now clearing to show scenes of devastation. A massive bomb had gone off in the City of London. No details as yet. I ran back outside. There was a taxi rank to my left. I ran to the first car. An old man in the classic Afghan chitrali cap regarded me as I skidded to a halt at his passenger door.

'Fare?'

He chewed betel and nodded slowly.

'Mate, I need to borrow your phone.'

His face clouded. I needed to pile this on. OK.

'Uncle. Do you love this country?'

'Of course I do. It has given me everything.'

'Then if you love it, please, please, and I ask you as a son of the Ummah, please lend me your phone for two minutes.'

I really didn't want to knock him out. He looked away for a while then shrugged and handed me his battered old Nokia and muttered something under his breath. I dialled the Colonel.

'Mahoney.'

'BOSS IT'S RIZ I'M IN WELWYN AND WE'VE - 'Calm down, Riz, deep breaths. We're a bit in the shit here.'

I could hear sirens in the background.

'Boss. The shooting target is STRATFORD.'

'OK. Got that. It's an unholy mess here. Liverpool Street is gone. All the firearms units were stood down because of the strike, and all the SF are at Shepherd's Bush and are pulling off because they think it's a false alarm. What happened?'

'Lord Khalil happened, that's what!'

An icy silence punctuated by the howl of sirens.

'I see. Where are you?'

'Welwyn Garden City, apparently. I just made the other bomb safe.'

'Good one, Riz. Can you get here?'

'Yes. If you ring Fuzz she'll pick me up.'

'I'll do that now. Wait one ...'

I hopped from foot to foot in impatience.

'... OK we just texted her your number. Riz, we need you here to - '

The line went dead. I looked at the phone. The cab driver was looking at me. Behind us a crowd was gathering from the post office. They were looking at the smoke on the horizon.

The phone rang.

'Salaams bhai!'

It was Fuzz.

'Where are you Riz?'

'Fuzz. I'm in Welwyn. Where are you?'

'We're at Elstree aerodrome. Hang on ...'

I could hear rustling. A map?

'... Riz, can you get to South Mimms services in ten minutes?'

I looked at the cab driver.

'Uncle, what is your name?'

'My name is Abdul Jamil Khan.'

'Mine is Rizwan Sabir. Abdul Jamil Khan, Sir, can you get me to South Mimms to meet some black-eyed maidens in ten minutes?'

He grinned with stained teeth.

'Now you're talking.'

33.

We drove. Abdul hit the radio for Capital and we listened to the chaos. The reports were conflicting. Dirty bomb. Fire at Liverpool Street. Electrical fault. Something at Shepherd's Bush. They were winning. They'd got them to go the wrong way. We hit the roundabout for the services at an insane speed as three emergency services vehicles barrelled past us south into London with sirens and lights on.

We screeched into the truck park at South Mimms and there, at the back, was a black Gazelle helicopter. I pointed at it.

'Uncle. See that? That's my ride.'

Abdul sat and stared open-mouthed at the sleek machine. I gave him the two twenties and gripped his shoulder. Then I jumped out and ran forward. The turbine on the chopper started to whine. Bang-Bang flung herself into my arms and I'd never seen a more beautiful sight. We hugged. She popped gum in my ear.

'Missed ya. Let's go.'

We ran under the rotors as they started to turn. I jumped into the front passenger seat. In the pilot's seat Fuzz grinned at me with crazy blue pinwheeling eyes and pointed at the headset hanging behind the seat. I put them on and listened in as the turbine went from a whine to a howl.

'Hey kid. Looks like we got some jihad on.'

'You don't say. Half the city is gone and they're about to hit Stratford shopping mall.'

Fuzz yanked up the collective and we roared into the air. She pulled a pair of aviator shades down over her eyes. The satnav display span up on the console.

'Anyone else inbound?'

'No. We're it.'

She shook her head and laughed.

'So we're it. Fasten your seatbelts brother and sisters, Stratford here we come. Better hold on - this thing goes like a fat kid after the last samosa.'

We climbed. Before us, in the distance, was a huge ugly wall of smoke near the Gherkhin. The City of London was a mess of fire and dust. Off to our left was our target. Westfield Stratford. Fuzz's voice came into our earphones.

'I figure seven minutes to target my darlings. Lock and load and I'll try and deal with traffic control.'

I spoke into the mike.

'What do we have on board ladies?'

Calamity's voice came into my headphones. 'Er ... we brought your HK. Fuzz has her gat. In back here we've got a Para Minimi and a cut-down M14 ... and some cough sweets.'

'You do realise we're probably all going to die, right?'

'Yes bro, we do. And it was an honour to fly with you.'

'OK. We need a recognition marker. Something to mark us out to the security forces.'

A silence.

'Got a sari in the back here. It's yellow.'

That would have to do.

'OK, tear some strips off, we make armbands out of it. One each.'

The radio screeched in all our headsets.

' Golf Charlie Kilo please resquawk IFF and state course .'

Fuzz barked a laugh.

'That'll be ATC Swanwick. No matter what I do or say now, they're about to scramble the Typhoon flight at Coningsby. So now we hit the deck. Hopefully they won't be able to pick us out of the ground clutter and we won't get a missile up the pipe. Hold on kids. Five minutes to target.'

We held on.

Calamity passed forward a scrap of cloth, a walkie-talkie, and my HK PDW. I loaded it and made safe. I pointed it down as helicopter drills required. I tied the cloth onto my left arm. In my earphones I could hear weapons being made ready. Fuzz was on to air traffic control as we went down to rooftop height. The North Circular flashed beneath us. It was crammed with traffic in both directions. I caught a fleeting glimpse of a billboard lit up with 'KEEP OUT OF LONDON TUNE INTO RADIO' as we thundered over it.

Here we went. I held onto a handhold. Fuzz was talking into her mike.

'London Centre this is Golf Kilo Charlie inbound to Stratford. Squawking 7700. Be advised we are KTS repeat Kilo Tango Sierra, please advise MOD and they can contact us on the emergency channel. Contact is Colonel David Mahoney, repeat, David Mahoney. Out.'

I was trying to guess how long it would take for a message to get to the Colonel. If his phone had cut out it meant the authorities had shut down the mobile networks in London and invoked MTPAS, the Mobile Telecommunication Privileged Access Scheme. Hopefully we had access to it on our secure sets. I couldn't remember if we could. Fuzz spoke in my ear.