The children ordered spaghetti carbonara followed by chicken. It was their regular favourite. Gloria thought I was a bad influence on their eating habits but, as I always pointed out to her, they never demanded salad when I had salad.

When I ordered the pappardelle it was Gloria who said, 'Give him a big portion; he hasn't eaten for a couple of days.'

Mario's face was inscrutable, but I said, 'Mario knows that's not true. I had lunch here yesterday with Dicky Cruyer.'

'You swine,' said Gloria. 'You told me you were going to diet.'

'I had to come,' I said. 'It was work. And Dicky was paying.'

Billy went off to the toilet. Mario had imported the urinals at tremendous expense from Mexico, and Billy liked to check them out whenever he visited the place.

Sally went with Mario to choose an avocado for Gloria. Sally considered herself a connoisseur of avocados. It was while we were on our own that Gloria said, 'Is Dicky Cruyer having an affair with your sister-in-law?'

'Not as far as I know,' I said truthfully, although not totally truthfully since George had told me she might be. 'Why?'

'I saw them in a Soho restaurant that night when my father took me to dinner to quiz me about why I wasn't sleeping at home at weekends.'

'It couldn't have been Tessa,' I said. 'She won't eat anywhere except at the Savoy.'

'Don't be flippant,' she said. She grinned and tried to slap my hand, but I pulled it away so that she made the cutlery jingle. 'Answer me. Am I right?'

'What did your father say that evening? You never told me about it.'

'Why don't you just answer my question?' she said.

'Why don't you answer my question?' I replied.

She sighed. 'I should never have fallen in love with a spy.'

'Ex-spy,' I said. 'I've given up spying a long tune ago.'

'You never do anything else,' she said. It was a joke, but it wasn't a joke.

We had to go out to dinner – to George and Tessa Kosinski's – that evening. But you can't go out to dinner after rain has reduced your hair to rat-tails. It was a special event, their housewarming, and we'd promised to go; but Gloria wailed that she couldn't. That was the predicament that faced us that Saturday afternoon. Had my wife, Fiona, ever been so childish and petulant, I would have dismissed such protests angrily, or at least with bad-tempered sarcasm. But Gloria was little more than a child, and I found the manner in which she treated such minor incidents as crises both silly and funny. How wonderful to be so young, and so unaware of the terror that the real world holds, that disarrayed hair can bring tears. How gratifying when one quick phone call and the price of a repair job at a crimping salon in Sloane Street can bring such a gasp of joy.

And if you'd told me that my reactions were the sign of a funda-mental flaw in our relationship, if you'd told me that these aspects of my love affair with her were only what could be expected when a man of forty falls in love with a woman young enough to be his daughter, I'd have agreed with you, I worried about it constantly and yet I always ended up asking myself whether such elements of paternalism weren't to be found everywhere. Maybe not in every happy marriage, but certainly in every blissful affair.

I was still careful, not to say wary, about the places I took her to and the people we mixed with. Not that I had an infinity of choices. A man without a wife discovers all kinds of things about his friends. When my wife first left me I'd expected that all my friends and acquaintances would be inviting me out – I'd heard so many wives complaining about how difficult it was to find that 'extra man' for dinner. But it doesn't work like that; at least, it didn't for me. A man separated from his lawful wife becomes a leper overnight. People – that is to say one's married friends – act as if a broken marriage is some kind of disease that might prove contagious. They avoid you, the party invitations dry up, the phone doesn't ring, and when you finally do get an invitation, you're likely to find yourself entertained alone on an evening when their attractive teenage daughters are not in the house.

The Kosinski's housewarming party was amusing enough. I suspected that this was a result of practice, for it was rumoured that George and Tessa were staging a series of such gatherings and representing each as the one and only. But the evening was none the worse for that. The guests, like the food, were decorative and very rich. The cooking was elaborate and the wines were old and rare. Tessa was amusing and George was friendly in a way that suggested that he liked to see me with Gloria; perhaps seeing us together removed any last feelings he had about me coveting his wife.

George's Mayfair flat was a glittering display of tasteful extravagance. The old Victorian dining table that had once belonged to George's poor immigrant parents was the only modest item of furniture to be seen. And yet this long table, so necessary for a big family and now fully extended, provided George with a chance to play host to sixteen guests with enough room at each place setting for three large polished wine glasses, lots of solid-silver knives and forks, and a big damask napkin. The other guests were a glamorous mixture that emphasized the different worlds in which George and Tessa moved: a bald stockbroker who, sniffing the claret admiringly, dropped his monocle into it; a heavily lacquered TV actress who would eat only vegetables; a Japanese car designer who drank nothing but brandy; a grey-haired woman who looked like a granny, ate everything, and drank everything and turned out to be a particularly fearless rally driver; a Horse Guards subaltern with shrill young deb; and two girls who owned a cooking school and had sent a prize student to cook for Tessa that evening.

None of the women – not even the gorgeous Tessa, flaunting a new green-silk dress that was all pleats and fringe – could compare with mine. Gloria's hair was perfect, and she wore a choker of pearls and a very low-cut white dress that was tight-fitting enough to do justice to her wonderful figure. I watched her all the evening as she effortlessly charmed everyone, and I knew beyond a doubt that I was seriously in love with her. Like all such London dinner parties it ended rather early and we were home and undressing for bed before midnight. We didn't read.

It was dark. I looked at the radio clock and saw that it was three-twenty in the morning as I became fully awake. I'd been sleeping badly for some time. I had a recurring dream in which I was swept away in the filthy swirl of some wide tropical river – I could see the palm trees along the distant banks – and as I drowned I choked on the oily scum. And as I choked I woke up.

'Are you all right?' said Gloria sleepily.

‘I all right.'

'I heard you coughing. You always cough when you wake up in the night like this.' She switched on the light.

'It's a dream I have sometimes.'

'Since that boy Mackenzie was killed.'

'Maybe,' I said.

'No maybe about it,' she said. 'You told me that yourself.'

'Switch the light off. I'll be all right now. I'll go back to sleep.'

I tried to sleep, but it was no use. Gloria was awake too, and after more time had passed she said, 'Is it about Bret? Are you worrying about Bret?'

'Why should I worry about him?'

'You know what I mean.'

'I know what you mean.' It was dark. I wanted a cigarette very badly, but I was determined not to start smoking again. Anyway, there were no cigarettes in the house.

'Do you want to tell me about it?'

'Not particularly,' I replied.

'Because I might be the mole?'

I laughed. 'No, not because you might be the mole,' I said. 'You've only been in the Department five minutes. You're very recently vetted. And with a Hungarian father you'd get a specially careful scrutiny. You're not the mole.'