You come into Arras just before six, the broad road shiny, lonely in the Sunday twilight. Up the long straight hill of the avenue Michonneau, and because you've got the Guide Michelinopen on your lap you warn him for the right turn just at the top. Just after that you're in the Grande Place.

At that time and day and season it looks like the crypt of a forgotten citadel, the rows of parked cars in the middle like stone coffins. Behind a hundred shuttered windows there must be light, warmth, people. There, or on a different planet.

'Where did they say?'

He nods to the right. 'The north-east corner. There.'

'Keep going. Around the far side.'

He keeps going. You make him park so we have a clear run for a fast take-off, because… well, just in case. The silence without the car engine and heater is just as you felt it would be. The crunch of the patches of frozen snow as you walk back zigzagging between the other cars is like broken glass. You reach the roadway just about twenty yards from the north-east corner, and still nobody waiting…

I run it like that, over and over, instant slow-motion replay, a constant deliberate bad dream, trying to work out what else I could have done.

There was just the one shot, and maybe I heard the thud as it went into his body. Then I was on my face in the roadway, gun held straight in front, pointing at the last pillar of the arcade. Running footsteps – more than one person, away down the side street from the corner. I scrambled on to my feet, but Fenwick began to groan. And then a nasty gurgling noise.

He'd fallen back in a sitting position against a big Citroen. There was a bit of blood on the front of his overcoat, but my hand came out dripping when I felt around the back. Exit wounds are like that. Half a dozen windows lit up as people opened the shutters, and one brave soul actually leant out. You don't always do that when you hear a gunshot in France.

I yelled,'Police! Téléphone! Docteur!'What was the French for 'ambulance'? Hell, it was a French word already.'Ombulonz!'

The figure ducked back in, so maybe he'd understood. Fenwick made another nasty noise and now blood was coming from his mouth. What the hell was I supposed to do? If he was bleeding that bad, he was bleeding a lot worse internally. In the end, I held a useless handkerchief to his back and tried to keep his head up until he died. By then I could hear the sirens.

There was a drain grating in the roadway nearby. Just before they got there, I shoved the gun and the belt holster down it. The holster I could buy again, but I'd be lucky to get another Walther PP chambered for.380.1 also had Fenwick's car keys, and when I stood up, I was holding his flat, square package.

Five minutes later, the place was a pool of light from car headlamps parked squintwise all round to block the area off. I was showing aninspecteurwho spoke pretty good English where I thought the shot had come from.

'Just only one?'

'Just one.' He didn't like that. Neither did I, but I wasn't going to offer any opinions.

He peered at the pavement, tapping my passport against his left hand.

'Ah!' He pounced on a tiny glint of brass, back against the wall under the arcade. Then he handed me back my passport and whistled up a sergeant. Between them, they picked up the cartridge case on the end of a pencil and marked the spot with a crayon.

'Neuf millimètres,'said the sergeant – just to show off. Theinspecteurgave him a look and he scuttled away, carrying the pencil and cartridge case like a little Olympic torch in front.

Theinspecteursaid, 'You just met Monsieur Fenwick on the car ferry, then?'

'That's right. He found I was going to Arras, so he offered me a lift. He was going on to Paris, himself.' I don't often get that many lies into three sentences.

But he just nodded. They hadn't searched either me or Fen-wick yet – that would come later – so they didn't know about the car keys.

'And why are you in Arras? '

'I was going to look at some First World War battlefields. My grandfather's buried near here.' The second half of that's true, actually.

'You liked him?' he asked innocently.

'Come off it. He was dead fifteen years before I was born.'

His mouth twitched a small smile. It had been a routine trick question. The real interrogation would also come later – and fairly soon now.

I held up my left hand, still wet with Fenwick's blood. 'Look – can I get the doctor to clean this up?'

He looked around the busy circle of light. The ambulance was still waiting while they photographed Fenwick from every angle.

He nodded. 'Okay.'

So he didn't suspect me of anything – yet. I walked across and got the police doctor to swab off my hand with some spirit. Except for the cuff of my sheepskin jacket, there wasn't any blood on my clothes. Maybe there's some instinct that keeps you away from other people's blood; I don't think it's just a matter of your profession.

'C'était votre ami?' he asked. Was that your friend? To him, it was just another job.

I shrugged.'Depuis quelques heures.'

He shook his head without meaning anything and checked my hands over for scratches, my fingernails for any interesting-looking dirt. Again, just routine.

Somebody by the body called,'Docteur Delansorne!'

He called back, then glanced at me.

'No thanks, I've seen…]e l'ai vu.'

He smiled a slightly superior smile and went. I leaned on the ambulance and looked around without moving my eyes. Nobody seemed to be looking, and three big steps would get me back out of the light. I did it in a dozen small, casual ones.

Then I was moving fast, stooping low and zigzagging across the rows of parked cars, down the Une of retreat – cover from view, cover from fire – that I'd planned for both of us. Just in case.

Maybe they didn't even hear the car start; maybe they heard it and it didn't mean anything to them; maybe they didn't immediately think of me taking the car – I don't know how many minutes' start I had. And when they searched Fenwick and found his green card insurance, they'd know it was a Rover 2000 and the number – but it doesn't say the colour.

For all that, I stayed off the autoroute. I cut across to Douai, and then hooked back again to come into Lille on the N25. I had to leave the car there: I couldn't get it across the Belgian frontier without the green card, and I wanted very much to be across the nearest frontier there was. Train to Brussels and a midnight flight back to London – just for the record. Off the record is the time just out of Douai when I got the shakes so hard I had to stop and get my duty-free bottle of Scotch out of my case in the boot.

Still, by then it had been a long day, even if I had been well paid for it.