'And I met his sister Poppy here in this house not so long ago. The last time you had me over for dinner.'

'Poppy's a darling. But Paul is a shifty bastard. Didn't you sell him that Ferrari of yours?'

'Shifty? And is that an opinion you've reached since the phone rang?' I asked. 'Yes, I sold him my car. I often wish I'd kept it. He's been through half a dozen since that one, and even with my car allowance I can't even afford a new Volvo.'

'I've always wondered if young Biedermann was in the spy game. He's perfectly placed; all that travelling. And he's egoistical enough to want to do it. But it sounds as if the other side got in first.'

'He's a creep,' I said.

'Yes, I know you hate him. I remember your lecturing me about the way he sold his father's transport yard. How would you like to go to Paris and sort this one out? It will just be a matter of a preliminary talk with the people who are holding him. By that time London will have got hold of whoever signed the "sacred" tag. Whoever signed the tag will have to go to Paris, that's the drill, isn't it?'

'Yes, it is,' I said. I had a cold feeling of foreboding. Whoever had signed the 'sacred' tag would have to go to wherever Biedermann was being held. There was no way out of that; it was mandatory. Anyone who knew I'd signed that 'sacred' tag could make me go anywhere they wanted me to go; all they had to do was to have Biedermann arrested, and put the NATO signal on the line. I hadn't thought of that when making Biedermann 'sacred', and now it was too late to change anything.

'Are you all right, Bernard? You've gone a nasty shade of green.'

'It was the breakfast I had at Lisl's,' I said hastily. 'I can't digest German breakfasts any more.'

Frank nodded. Too much of an explanation. That was the trouble when dealing with Frank and Werner; they knew me too well. That was the trouble when dealing with Fiona too. 'Just hold the fort in Paris until London sends whoever signed that tag. I'm very short of people this week, and since you're on your way back to London anyway… You don't mind, do you?'

'Of course not,' I said. I wondered whether the person who had masterminded this one had known I'd be with Frank today, or whether that was just a lucky coincidence for them. Either way the result was the same. Sooner or later I would have to go to Paris. I was the mouse in the maze; start running, mouse. 'Can you let me have a hand-gun, Frank?'

'Now? Right away? You do come up with some posers, Bernard. The army look after our hardware nowadays, and it takes a day or two to get the paperwork through channels and make an appointment with the duty armoury officer. I could have it by the end of the week. What exactly do you want? I'd better write it down so that I don't get it wrong.'

'No, don't bother,' I said. 'I just wanted to know what the score was, in case I was here and needed a gun some time.'

Frank smiled. 'I thought for one moment you were thinking of taking a gun to Paris. That would mean one of those non-ferrous jobs – airport guns they call them nowadays – and I'm not sure we have any available.' He was relieved, and now he placed a hand on the phone as he waited for it to ring again. 'My secretary will be phoning back with all the details, and then the car can get you to the airport in time for the next plane.' He consulted his gold wrist-watch. 'Yes, it will all fit together nicely. What a good thing you were here when it happened.'

'Yes,' I said. 'What a good thing I was here when it happened.'

Frank must have heard the bitterness in my voice, for he looked up to see my face. I smiled.

Charles de Gaulle is the sort of futuristic airport that you might find inside a Christmas cracker that was made in Taiwan a long time ago. Overhead the transparent plastic was discoloured with brown stains, moving staircases no longer moved, carpeting was threadbare, and the imitation marble had cracked here and there to reveal a black void into which litter had been thrown. There were long lines to get coffee and even longer ones to get a drink, and the travellers who liked to eat while sitting down were sprawled on the floor amid the discarded plastic cups and wrappings from microwave-heated sandwiches.

I was lucky. I avoided the long lines. A uniformed CRS man met me as I stepped from the plane. He took my bag and conducted me through customs and immigration, with no more than a perfunctory wave to the CRS officer in charge there. Now he opened a locked door that admitted me to another world. For behind the chaotic slum that the traveller knows as an airport there is another spacious and leisurely world for the staff. Here there is an opportunity to rest and think and eat and drink undisturbed, except for the sound of unanswered telephones.

'Where are you holding him?' I asked the CRS man as he held the door open for me.

'You'll have to talk to Chief Inspector Nicol first,' said the CRS man. We were in a small upper section of the main building that is used by the police. Most of the offices on this corridor were used by the Compagnie Républicaine de Sécurité who manned the immigration desks. But the office into which I was taken was not occupied by a man who checked passports. Chief Inspector Gérard Nicol was a well-known personality of the Sûreté Nationale. 'The cardinal' they called him, and he was senior enough to have his own well-furnished office in the Ministry building on the rue des Saussaies. I'd met him several times before.

'Chief Inspector Nicol; I'm Samson,' I said as I went into his office. I kept it very formal. French policemen demand politeness from colleagues and prisoners alike.

He looked me up and down as if deciding it was really me. 'It's a long time, Bernard,' he said finally. He was dressed in that uniform that Sûreté officers wear when they are not wearing uniform: dark trousers, black leather jacket, white shirt and plain tie.

'Two or three years,' I said.

'Two years. It was the security conference in Frankfurt. There was talk of you getting a big promotion.'

'Someone else got it,' I said.

'You said you wouldn't get it,' he reminded me.

'But I didn't believe it.'

He protruded his lower lip and shrugged as only a Frenchman shrugs. 'So now they are sending you to charm us into letting you have custody of our prisoner?'

'What is he charged with?' I asked.

By way of answer, Nicol picked up a transparent bag by the corner so that the contents fell on to the desk-top. A US passport crammed with immigration stamps of everywhere from Tokyo to Portugal, a bunch of keys, a wrist-watch, a crocodile-skin wallet, a gold pencil, a bundle of paper money – German and French – and coins, a plastic holder containing four credit cards, a packet of paper handkerchiefs, an envelope defaced with scribbled notes, a gold lighter and a packet of the German cigarettes – Atika – that I'd seen Biedermann smoking. Nicol picked up the credit cards. 'Biedermann, Paul,' he said.

'Identification from a credit card?' I sorted quickly through Biedermann's possessions.

'It's more difficult to get a credit card these days than to get a carte de séjour,' said Nicol sorrowfully. 'But there's a California driving licence with a photo if you prefer it. We haven't charged him with anything yet. I thought we'd wait until you arrived.'

'That's most considerate of you,' I said. I put the packet of German cigarettes into my pocket. If Nicol saw me do so he made no comment.

'We always try to oblige,' said Nicol. There is no habeas corpus in French law. There is no method whereby a man unlawfully detained may be set free. The Prefect of Police doesn't need a formal charge or evidence that any crime has been committed; he needs no judicial authority to search houses, issue warrants and confiscate letters in the post. He can order the arrest of anyone without even having evidence that any crime has been committed. He can interrogate them and then hand them over for trial, release them or send them to a lunatic asylum. No wonder French policemen look so relaxed.