'She's at evening class,' I said. I knew it would produce a hoot of laughter and I wasn't disappointed.

'Evening classes, darling? How old is she? She looks as if you might have kidnapped her from the fifth form.'

'She's studying economics,' I explained. 'She's determined to go to Cambridge.'

'What a coup that would be for an unlettered oaf like you, darling. A wife educated at Oxford and a mistress at Cambridge.' She was still standing behind me, but when I tried to grab her wrist she ducked away.

'It's about you and Dicky,' I said, determined to broach the subject.

'I knew that was coming. I could see it in your face,' she said.

'You've worked hard to avoid talking about it,' I said. 'But there's something you ought to know.'

'Don't tell me Dicky Cruyer is married or something awful like that,' she said. She sank down in the soft chair, kicked off her gold evening shoes, and put her feet on the coffee table in such a way that her toes could touch the ice bucket.

'Daphne is furious,' I said.

'I told him she'd find out about us,' said Tessa calmly. 'He's so careless. It's almost as if he wants everyone to know.'

'A friend of Daphne's saw you at a hotel near Deal.'

'I knew it,' she said. She laughed. 'Dicky packed both bags and forgot that I always leave my nightdress under the pillow… in case there's a fire or something. I unpacked when I got home, but at first I didn't notice the nightgown was missing. Then I absolutely panicked.' She drank some champagne. She was enjoying the story, enjoying it more than I was. 'You can imagine what I was thinking. Dicky had put his real address in the hotel register – he's such a chump – and I had visions of the hotel sending my wretched nightie to Daphne with a note saying she'd left it behind or something.'

She looked at me, waiting for me to ask what she did next. 'What did you do next?' I asked.

'I couldn't phone Dicky; he's furious if I phone him at the office. But I couldn't think how to put it to the hotel people. I mean, how can you explain that you don't want them to send your nightie back? Do you tell them to give it to Oxfam or say you've just moved house? It's impossible. So I jumped into my car and trundled all the way back to Deal again.'

'Did you get it back?'

'Darling, it was an absolute riot. This lovely lady in the reception said she'd worked in big hotels all over Europe. No hotel ever returns nightgowns or articles of ladies' underwear to the address in the register, she said. They wait until there is a query about it. Then, darling, she showed me this immense cupboard full of flimsy garments left behind after weekends of illicit passion. You should have seen them, Bernard. I blushed at some of the things in that cupboard.'

'So all was well?' I wanted to talk about her affair with Dicky, but I could see she was trying to spin things out until George got back and so avoid it.

'I said to this amusing lady that we should go into business and buy all these wonderful things from hotels and sell them. I even mentioned it to the people on this committee I'm on – it's a children's charity – but you should have seen their faces. They're all old fogies with tinted hair and fur coats. You'd have thought I'd suggested opening a brothel.'

'You didn't explain to them exactly how you obtained this information?'

'I told them it had happened to a friend of mine.'

'Not a very convincing subterfuge,' I said.

'No, well, I'm not in that world, am I?' she said. That remark was aimed at me.

'It wasn't the nightdress. It was a friend of Daphne who saw you.'

'And my mind has been buzzing ever since you said that just now. I can't think of any familiar face there that weekend.'

'Daphne's talking about a divorce.'

'She always says that,' said Tessa. She flicked her hair back and smiled defensively.

'Always? What do you mean, always?'

'You know very well that I had a little fling with Dandy Dicky last year, or was it the year before? We talked about it one evening. I remember you were very toffee-nosed.'

'If Daphne goes to a lawyer, it could become a rotten business, Tess.'

'It will be all right,' she said. 'I know you mean well, Bernard darling. But it will be all right.'

'If I believed that, I wouldn't be sitting here talking about it. But I know Daphne well enough to think she could be serious.'

'Divorce? What about the children? Where would she live?'

'Never mind Daphne's problems. If she starts making a fuss, you'll have enough of your own. She wants me to introduce her to George.'

'That's ridiculous,' said Tessa.

'Dicky would be the real loser,' I said. 'Publicity such as a nasty divorce action would destroy his career.'

'Don't say they'd fire him – I know that's not true.'

'They probably wouldn't sack him, but he'd be posted to some lousy place on the other side of the world and left there to rot. The Department doesn't like publicity, Tessa. I don't have to draw you a diagram, do I?'

Her flippant attitude had changed now. She took her feet off the table and drank some champagne, frowning deeply as she considered her position. 'George would be furious,' she said, as if he'd be more furious about the publicity than about her infidelity.

'I thought you were trying to put your marriage together again,' I said. 'I remember you talking to me and saying that George was the most wonderful husband in the world and that all you wanted to do was to make him happy.'

'I do, darling, I do. But it won't make him happy to be portrayed as the wronged husband and have his photo in all those lousy newspapers. I'll have to talk to Daphne. I must make her see sense. It would be insane for her to leave Dicky over such a stupid little thing.'

'It's not a "stupid little thing" to her,' I said. 'And if you start talking to her in that fashion, you'll only make things worse.'

'What do you want me to say?'

'Don't make it sound as if you're doing it for me,' I said testily. 'I can't tell you what to say. But the only thing that Daphne will want to hear is that you're not going to see Dicky any more.'

'Then, of course, I'll tell her that.'

'You've got to mean it, Tessa. It's no good just patching it over… You're not in love with him or anything, are you?'

'Good heavens, no. Who could be in love with him? I thought I was doing Daphne a favour, to tell you the truth. I don't know how anyone can bear Dicky round them all the time. He's awfully wearing.'

I listened to her protests with a healthy mistrust. I didn't know much about women, but I knew that such strenuous denials could sometimes be a sign of profound passion. 'Tell her you're sorry. It's time you stopped all this nonsense, Tessa. You're not a child any longer.'

'I'm not old and ugly,' she said.

'No, you're not. Perhaps it would be better if you were old and ugly. George would remain loyal, no matter how old and ugly you were, and you'd realize what a good husband you have.'

'You men all stick together,' she said sullenly.

'You make a lot of people unhappy, Tessa. I know you don't see it like that, but you're a troublemaker. You had a rich father who gave you everything you ever asked for, and now you think you can have anything you want, no matter who it belongs to or what the consequences may be.'

'You have a terrible tendency to play the amateur psychologist, Bernard. Did I ever tell you that?'

'I hate amateur psychologists,' I said. She always knew how to needle me. I drank my champagne and stood up.

'Don't give me that injured-pride look, darling. I know you're trying to help.'

'If you want me to talk to Daphne, I will. But I won't do it unless I get a sincere promise from you that the affair is at an end.'

She stood up too. She came close and stroked the lapel of my jacket. Her voice was a purr. 'You're very masterful, Bernard. That's a very attractive quality in a man. I've always said that.'