This evening the front drive was empty, the cars locked away. Her parents were spending ten days at their holiday villa in Spain. Gloria went through an elaborate routine of unlocking doors and switching off burglar alarms within the prescribed sixty seconds. Then we went inside.

The house smelled of a syrupy perfume resembling violets. Gloria said their cleaning woman was coming in every morning and systematically 'shampooing' the carpets. 'I'll make you a cup of coffee,' she suggested. I agreed. It was interesting to watch her in her parents' home. She became a different person: not a more diffident or childlike one, but vicariously proprietorial, as if she were a real estate clerk showing the house to a prospective purchaser.

We sat in the kitchen. It was a designer kitchen: Marie-Antoinette at her most rustic. We sat on uncomfortable stools at a plastic Louis Seize counter and watched the coffee dripping through the machine. The overhead light – bleak and blue – came from two long fluorescent tubes which buzzed.

It gave me a chance to look at her. All day she'd been her usual warm and good-natured self. It was almost as if she'd forgotten yesterday's clash. But she hadn't. She didn't forget anything. How beautiful she was, with all that energy and radiance that is the prerogative of youth. No wonder people such as Dicky envied me. Had they realized that Fiona would soon be returning perhaps they would have envied me even more. But for me it was a miserable dilemma. I couldn't look at Gloria without wondering if I was going to be able to handle the personal crisis that Fiona's return would bring. The idea of Fiona being kept in deep cover for six months made it even more irresolvable. And what about the children?

'I don't think you've been listening to a word of what I've said,' I suddenly heard Gloria say.

'Of course I have,' and with an inspired evasion tactic I added, 'Did I tell you who Dicky is going to Berlin with?'

'No.' Her eyes were wide open. She swung her blonde hair back and held it as she leaned very close so that I was conscious of the warmth of her body. She was wearing a crimson shirt dress. On most women it would have looked awful but she brought a dash to such cheap bright clothes, just as small children so often do.

'Tessa,' I said.

'Your Tessa?'

'My sister-in-law. Yes.'

'So Tessa is up to her old tricks. I thought the affair with Dicky was over long ago.'

'Yes. That's been puzzling me too.'

'It's hardly a puzzle, darling. People like Dicky, and Tessa too, are capricious.'

'But Dicky was warned off last time.'

'Warned off seeing Tessa? By Daphne, you mean?'

'No. The Department didn't like it. Clandestine meetings with the sister of a defector looked like a potential security risk.'

I'm surprised Dicky took any notice.'

'You shouldn't be. Dicky may wear funny bow ties and play the Bohemian student, but he knows exactly how far to go. When the bugle sounds and the medals are being awarded he toes the line and salutes.'

'Except when it comes to Tessa you mean. Perhaps it's love.'

'Not Dicky.'

'So perhaps he's had official permission to bed Tessa,' she joked.

'That's what it must be,' I agreed, and not long afterwards I was to reflect upon her joke. 'Perhaps what Dicky found irresistible was not having to pay her fare.'

'What a swine he is. Poor Daphne.' She poured the coffee and, in a dented biscuit tin, discovered a secret supply of chocolate biscuits.

'And he's booked his hotel in my name. What about that?'

She took it very calmly. 'Why?'

'I suppose he's going to tell Daphne some story about me going off with Tessa.'

'But you're not going?'

'I'm afraid I am.'

'The weekend?' I nodded. She said, 'I told the Pomeroys to come to dinner on Saturday.'

'Who the hell are the Pomeroys?'

'The parents of Billy's friends. The children were eating with them last night. They are terribly kind.'

'You'll have to put them off,' I said.

'I've put them off twice before when you went on trips.'

'It's an order from the D-G. You know what that means. There's no way I can get out of it.'

'The weekend?'

'I go on Friday morning; back on Monday or Tuesday. Dicky's secretary will know what's happening over there.'

'And on Sunday there's Billy's car club meeting. I said you'd take him.'

'Look! It's not my idea, darling.'

For a long time she drank her coffee without speaking. Then she said, 'I know it's not,' as if responding to some other question that only she knew about. 'But you said there was going to be a party at Werner's hotel. I know you wanted to go.'

'It's just to promote the hotel. We'll go some other time. They are always having parties, and anyway it would be no fun without you.'

After the coffee I went with her to the room she had when living here with her parents. They kept it for her as if they were expecting her every night. Toys, teddy bear, dolls, children's books, school books, a Beatles poster on the wall. The bed had been made up with freshly laundered linen. Taking her away from them was my doing and there were times when I felt bad about it. And I hadn't even married her. How would I feel if some time my daughter Sally disappeared with some middle-aged married man? Sometimes I wondered how I would be able to deal with the inevitable separation from the children. Would I find myself keeping their bedrooms as shrines at which I could pray for a return of their childhood days with me?

Looking out from the bedroom window I could see the flat roof of a large single-story building that had been added to the house. Seeing me looking at it, Gloria said, 'I cried when they ruined my view of the garden. There was a lovely chestnut tree there and a rhododendron.'

'Why did you need extra space?'

'It's a surgery and workshop for Daddy.'

'I thought he had a surgery in town.'

'This is for special jobs. Didn't you know?'

'Why would I know?'

'Want to see? It's where he does work for the Department.'

'What kind of work?'

'Come and see.'

She got the big bunch of keys that her father had left with her and we went down into the neat little dental surgery. She opened the door, and while she searched for the light switches the room was only lit from a glass box in the corner where tropical flowers appeared under ultraviolet lights. When she switched on the light, apart from seeming unusually cramped with apparatus, it was like any other dentist's workplace: a modern fully adjustable chair and elaborate drill facing a large window. There was a big ceramic spittoon, a swivelling cold-light and many glass-fronted instrument cabinets, packed with rows and rows of curiously shaped drills, forceps, sealers and other spiky implements.

Gloria went round the room naming the equipment and describing what it was for. She seemed to know a lot about dentistry despite having resisted her father's wish that she should become one. This she said was her father's secret sanctum.

'Who comes here for treatment?' I asked.

'Not so many nowadays, but I can remember a time when Daddy worked more hours here than at his proper surgery. I remember one poor Polish boy who was in the chair for at least six hours. He was so exhausted that Daddy let him come and sit in the drawing room with Mummy and me, to take his mind off things.'

'Agents?'

'Yes, of course. At university, Daddy wrote a thesis on the history of European dentistry. After that he began his collection of old dental tools. Now he can look into anyone's mouth and know where they had their teeth fixed, and when. Look at that.' She held up a particularly barbarous-looking instrument. 'It's very old… from Russia.'

'I was lucky,' I said. 'My teeth were always fixed by a Berlin dentist and my cover story was always German. I didn't have to have any of my dental work changed.'