Andy McNab - Zero hour

Chelmsford Saturday, 20 March 11.16 hrs Liverpool Street wouldn't be too far now. I was at a table seat with my back to the engine. My head rested against the window. My eyes were closed and the motion of the train made it harder not to sleep.

A bunch of squaddies had got on at Colchester and taken the table across the aisle. All four were in jeans and trainers, and 2 Para sweatshirts so we knew who they were. Four regulation-issue black day sacks sat on the racks above them.

I caught snatches of banter between dozes. It sounded like they had a weekend off and were looking forward to a night on the town and a cheap room at the Victory Services Club at Marble Arch. I'd stayed there once as a Green Jacket, off to Buckingham Palace to get a medal from the Queen.

I would have been about the same age as these guys, but not half as excited. They'd got discounted tickets to the Chelsea game on Sunday from a new website just for squaddies.

I jogged myself awake. ''Scuse me, lads – Chelsea are at home, aren't they?'

The one nearest to me answered. 'Yeah, against Blackburn.'

'What time's kick-off?'

'Four.' He pointed at my head. 'But you'd better leave that at home, know what I mean?' He didn't actually tell me I was a wanker, but I could see he was tempted.

I smiled. I had a Man U baseball cap on. It wouldn't be the cleverest thing to wear anywhere near Stamford Bridge, but it went very nicely with the baggy brown raincoat and geeky reading glasses I'd kitted myself out with at the British Heart Foundation shop in Ipswich. They rattled against the window as I watched the scenery become more built up. The baby Paras got more excited with every passing minute. They planned to drink the city dry tonight and then shag it senseless before watching the Blues hammer Blackburn.

Until I got back to Anna, I was going to change my appearance at every bound. I'd ditched my Timberlands in favour of a pair of plastic-soled shoes that were already half dead when I'd handed over the two pounds for them.

I had to shed my skin twice a day. This country has more CCTV than the rest of the world put together. That was why I was wearing the glasses and the cap with a big brim. They've got facial recognition and software that can analyse the way you walk.

Once I'd got to London, I'd take on another look. And this was the last time I'd be using buses and trains. They all had cameras. I'd pay cash for everything and stay away from my flat, my car, my London life. They must know by now that I'd dropped out of sight, and that Bradley wasn't delivering Lily on a plate. The voice-recognition gear and all the Tefalheads' other toys at GCHQ would be whirring away looking for the shape, sound or PIN of Nick Stone.

I watched rows and rows of thirties bay-windowed houses flash by as we hit the suburbs. My head started to hurt, but only where the bite on top of it vibrated against the window.

I closed my eyes again as the Paras got even more lairy about the weekend ahead. Another four cans of Carling came out of a day sack.

London 13.23 hrs I legged it the fifteen minutes or so to Brick Lane. I'd never understood why people liked Ye Olde East End, the area rubbing up against the financial centre. I'd spent my whole childhood in a shit hole like that, trying to dig my way out. But today I was glad it was so close to Liverpool Street. It had loads of charity and corner shops.

Walking back from Brick Lane towards Shoreditch, I kept my eyes open for somewhere to change into my new clothes. I found the Hoxton Hotel, a monument to glass and steel. I looked like Tracey Emin's unmade bed, but so did many of the uber-trendy lads round here. This was jeans-hanging-round-your-thighs territory.

I went into the toilets, quickly washed my face and splashed my hair to smooth it down. I emerged wearing a green parka, brown cords, blue baseball cap, and cheap Timberland rip-offs that were so scuffed and knackered they looked the height of Hoxton chic.

I made sure the blue cap shadowed my face, dumped my train clothes in a bin and turned towards the City again. A cafe selling salt-beef sandwiches took another few quid off me. I munched as I walked and tried to work out my plan of action.

The later editions were already showing colour pictures of the burnt-out silo and blaming Muslim fundamentalists. 'Reliable sources' said the local Muslim population had had its fill of Amsterdam's decadence, and Iranian-funded extremists had stepped in to take direct action. The papers said that, in response, the Brits, along with the rest of Europe and the US, had taken their own threat matrix up a level as the UK waited to see if it would be next on the attack list.

I got my salt beef down me and felt better than I had at any time since the Vietnamese with Jules.

I passed a pound shop and picked up a shrink-wrapped pack of steak knives with plastic handles pretending to be wood and the world's biggest fuck-off pair of pliers. Back out on the main I hailed a cab.

'Regent's Park tube, mate.'

He was happy. It was a good fare. And I was happy because the cab had no cameras. I got my head down and pretended to sleep. We moved slowly towards the West End. We were caught in stop-start traffic on Marylebone Road.

I leant forward. 'I tell you what, mate, quick change of plan. Can you go down Harley Street and drop me off near John Lewis?'

'No drama.' He looked around, both hands off the wheel, as we ground to a halt yet again. 'I blame Ken Livingstone. Them fucking bendy buses fucking everything up.'

We turned left into Harley Street and followed the one-way system south towards Cavendish Square, Mercs and Rolls-Royces parked up every few metres with their four-ways on.

'Some fucking money down here and no mistake.'

I looked from side to side and nodded. But I wasn't admiring the cars or the shiny brass plates: I was scanning the street for a stakeout on the clinic. It was a known location. Being paranoid pays dividends in this business.

I wasn't expecting to see anything as obvious as a two-up in a smoked-glass MPV or guys hanging around in Ray-Bans. If anything, it would be somebody in the building, or camera surveillance. The Firm could have requisitioned a CCTV camera a kilometre away and zoomed in on the entrance on twenty-four-hour soak.

The clinic was on the first floor of the building to my left as we carried on south. I looked up at it through my new thicker-rimmed glasses. The chandelier burnt away in the consulting room. The lights were on; I hoped somebody was at home.

We got to the bottom of Harley Street and turned left into the square.

'Just here will be fine, mate.'

The fare was twenty-six pounds. I gave him three tens and told him to keep the change.

It looked like I'd made his day. 'Hang about… here you go, mate. For you.' He passed me a couple of clean receipts.

I smiled to myself as he drove away. Maybe I'd fill them in and present them to Jules as expenses.

I brought up my hood as I crossed the bottom of Harley Street and headed back the way we'd come. I must have looked like the guys at the Bender checkpoint. The clinic was now across the road, to my right. I'd done the drive-past, and now I was going to do the walk-past.

I hoped he was there. I hadn't called ahead. The only time you ever make contact with the target is when you either grip him or drop him.

The sky had been threatening rain, and it finally started as I drew level with the clinic. I kept my hands in the chest-height pockets of the parka, head down but eyes up, trying to catch a glimpse of Kleinmann thrusting a fistful of leaflets at a new victim. There was no one in sight.

Unless there was an exit at the rear, he could only go left or right. There were cars parked outside, but mostly with uniformed drivers. Chances were, he'd turn left and head for Oxford Street.