'I'll think about it,' I promised, although my mind was made up already, and he could discern that from the tone of my voice.

'You could come down here any time and see them, Bernard. I'm sure I don't have to tell you that.'

'I said I'd think about it.'

'And don't go reporting Fiona's Porsche as stolen. I sent my chauffeur to get it and it will be advertised for sale in next week's Sunday Times. Better to get rid of it. Too many unhappy memories for you to want to use it. I knew that.'

'Thanks, David,' I said. 'You think of everything.'

'I do but try,' he said.

Despite my tiredness I didn't sleep well after my return from Leith Hill. The air was warm and I left the bedroom window open. I was fully awakened by the ear-piercing screams of turbo-fans, and the thunder of aircraft engines, throttles opening wide to compensate for flap drag. The approach controllers at London Heathrow like to send a few big jets roaring over the rooftops about 6.30 each morning, just in case any inhabitants of the metropolis oversleep.

The radio alarm clock was tuned to Radio 3 so that I could hear the seven o'clock news bulletin and then spend fifteen minutes on the exercise bike to the sounds of Mozart and Bach. Since living alone I'd connected the coffee-machine to a time-switch so that I could come downstairs to a smell of fresh coffee. I opened a tin of Carnation milk and found a croissant in the bread-bin. It was old and dried and shrivelled like something discovered in a tomb of the Pharaohs. I chewed it gratefully. I hadn't had a decent meal since well before getting on the plane. But I wasn't hungry. My mind was fully occupied with thoughts of the children and the conversation I'd had with my father-in-law. I didn't want to believe him but his warnings about money worried me. He was seldom, if ever, wrong about money.

I was outside in the street, unlocking the door of my car, when the girl approached me. She was about thirty, maybe younger, dark-skinned and very attractive. She was wearing a nurse's uniform complete with dark-blue cloak and a plain blue handbag. 'My damned car won't start,' she said. Her accent was unmistakably West Indian; Jamaica, I guessed. 'And matron will kill me if I'm not at St Mary Abbots Hospital at eight forty-five. Are you going anywhere in that direction? Or to somewhere I can get a taxi?'

'St Mary Abbots Hospital?'

'Marloes Road near Cromwell Road, not far from where the air terminal used to be.'

'I remember now,' I said.

'I'm sorry to trouble you,' she said. 'I live across the road at number forty-seven.' It was a large house that some speculator had converted into tiny apartments and then failed to sell. Now there was always a For rent' sign on the railings and a succession of short-term tenants. I suppose it was the sort of place that my father-in-law would like to put me in. She said, 'There is something wrong with the starter, I think.'

I got in and leaned across and opened the passenger door for her. 'The staff nurse is a bitch,' she said. 'I daren't be late again.'

'I can go through the park,' I said.

She decorously wrapped her cloak around her legs and put her handbag on her lap. 'It's very kind of you. It's probably miles out of your way.'

'No,' I said. In fact it was a considerable detour but the prospect of sitting next to her for twenty minutes was by no means unwelcome.

'You'd better fasten your seat belt,' she said. 'It's the law now, isn't it?'

'Yes,' I said. 'Let's not break the law so early in the morning.'

She fastened her own seat belt and said, 'Do you follow the cricket?'

'I've been away,' I said.

'I'm from Kingston, Jamaica,' she explained. 'I had five brothers. I had to become interested in cricket; it was all they ever talked about.'

We were still talking about cricket when I came out of the park and, no right turn being permitted, continued south into Exhibition Road. As I stopped at the traffic lights by the Victoria and Albert Museum she broke into my chatter about England's poor bowling against Australia last winter by saying, 'I'm sorry to have to do this to you, Mr Samson. But you're going to turn west on to Cromwell Road when we've been round this one-way system.'

'Why? What do you mean?' I turned my head and found her staring at me. She didn't answer. I looked down and saw that she was holding a hypodermic on her lap. Its needle point was very close to my thigh. 'Keep your eyes on the road. Just do as I say and everything will be all right.'

'Who the hell are you?'

'We'll drive out along the Cromwell Road extension to London Airport. There's something I have to do. When it's done you'll be free to go wherever you have to go.' She reached up with her free hand and tilted the driving mirror so that I could not see the traffic behind.

'And if I slam on the brakes suddenly?'

'Don't do that, Mr Samson. I am a qualified nurse. My papers are in order, my story is prepared. What I have in this syringe will take effect within seconds.' She still had the West Indian accent but it was less pronounced now, and there was a change in her manner too. Less of the Florence Nightingale, more of the Jane Fonda. And she didn't say 'sorry' or 'thank you' any more.

I was constrained by the seat belt. I could see no alternative to driving to Heathrow. She switched on the car radio. It was tuned to Radio 4 so we both listened to 'Yesterday in Parliament'.

'I'll say this again,' she said. 'No harm is intended to you.'

'Why the airport?'

'You'll understand when we get there. But don't think there is any plan to abduct you. This just concerns your children and your work.' We were driving behind a rusting old car that was emitting lots of black smoke; on the back window there was a sticker saying 'Nuclear Power – No Thanks'.

When we got to the airport she directed me to Terminal 2, used by non-British airlines mostly for European services. We passed the terminal main entrance and the multi-storey car-park that serves it, and continued until we came to a piece of road that leads on to Terminal 3. Despite the yellow lines and 'No parking' signs, there were cars parked there. 'Stop here,' she said. 'And don't look round.' Carefully, and without releasing her hold of the hypodermic or looking away from me, she reached back to unlock the nearside rear door.

We were double-parked near two dark-blue vans. I heard my car door open and felt the movement of the suspension as it took the weight of another passenger. 'Drive on. Slowly,' said the nurse. I did as I was told. 'We'll go back through the tunnel. Then down to the motorway roundabout, keep going round it and back to Terminal 2 again. Do you understand that?'

'I understand,' I said.

'He's all yours,' the nurse said to the person in the back seat, but she kept her eyes on me.

'It's me, darling,' said a voice. 'I hope I didn't terrify you.' She couldn't eliminate that trace of mockery. Some people didn't hear it but I knew her too well to miss that touch of gloating pride. It was my wife. I was numb. I'd always prided myself on being prepared for anything – that's what being a professional agent meant – but now I was astonished.

'Fiona, are you mad?'

'To come here? There is no warrant for my arrest. I have changed my appearance and my name… no, don't look round. I don't want you unconscious.'

'What's it all about?' To keep me driving was a good idea; it limited my chances of doing anything they didn't want me to do.

'It's about the children, darling. Billy and Sally. I went to see them. I waited on the route between your mother's house and the school. They looked so sweet. They didn't see me, of course. I had to watch out for your bloodhounds, didn't I? They both wore matching outfits; acid green with shiny yellow plastic jackets. I'm sure Daddy sent them. Only my father has that natural instinct for the sort of vulgarity that children always love.'