'Yes, a few times, but it must be about six years ago… and I don't know anyone ' I stopped, puzzled, not knowing what kind of response he wanted.

'Do you know about this train?' he said. 'The Transcontinental Mystery Race Train? Ever heard of it?'

'Um,' I said, reflecting. 'I read something about it the other day. A lot of top Canadian owners are going on a jolly with their horses, stopping to race at tracks along the way. Is that the one you mean?'

'It is indeed. But the owners aren't all Canadian. Some of them are American, some are Australian and some are British. One of the British passengers is Julius Filmer.'

'Oh, 'I said.

'Yes, oh. The Canadian Jockey Club has given its blessing to the whole affair because it's attracting world-wide publicity and they are hoping for bumper attendances, hoping to give all Canadian racing an extra boost. Yesterday, my counterpart, Bill Baudelaire, told me he'd been talking with the company who are arranging everything-they've had regular liaison meetings, it seems-and he found there was a late addition to the passenger list, Julius Filmer. Bill Baudelaire of course knows all about the conspiracy fiasco. He wanted to know if there wasn't some way we could keep the undesirable Mr Filmer off that prestigious train. Couldn't we possibly declare him persona non grata on all racetracks, including and especially Canadian. I told him if we'd had any grounds to warn Filmer off we'd have done it already, but the man was acquitted. We can't be seen to disgrace him when he's been declared not guilty, we'd be in all sorts of trouble. We can't warn him off for buying two horses from Gideon. These days, we can't just warn him off because we want to, he can only be warned off for transgressing against the rules of racing.'

All the frustrated fury of the Jockey Club vibrated in his voice. He wasn't a man to take impotence lightly.

'Bill Baudelaire knows all that, of course,' he went on. 'He said if we couldn't get Filmer off the train, would we please get one of our grandees on. Although the whole thing is sold out, he twisted the arms of the promoters to say they would let him have one extra ticket, and he wanted one of our Stewards, or one of the Jockey Club department heads, or me myself, to go along conspicuously, so that Filmer would know he was being closely watched and would refrain from any sins he had in mind.'

'Are you going?' I asked, fascinated.

'No, I'm not. You are.'

'Um…' I said a shade breathlessly, 'I hardly fit the bill.'

'I told Bill Baudelaire,' the Brigadier said succinctly, 'that I would send him a passenger Filmer didn't know. One of my men. Then if Filmer does try anything, and after all it's a big if, we might have a real chance of finding out how and what, and catching him at it.'

My God, I thought. So simple, put like that. So absolutely impossible of performance.

I swallowed. 'What did Mr Baudelaire say?'

'I talked him into agreeing. He's expecting you.'

I blinked.

'Well,' the Brigadier said, 'not you by name. Someone. Someone fairly young, I said, but experienced. Someone who wouldn't seem out of place…' his teeth gleamed briefly '… on the millionaires' express.'

'But' I said, and stopped dead, my mind full of urgent reservations and doubts that I was good enough for a job like that. Yet on the other hand, what a lark.

'Will you go?' he asked.

'Yes,' I said.

He smiled. 'I hoped you might.'

Brigadier Catto, who lived ninety miles from London in Newmarket, was staying overnight, as he often did, in a comfortable bedroom upstairs in the club. I left him in the bar after a while and drove the last half-mile home to where I lived in a quiet residential street in Kennington.

I had looked in that district for somewhere to put down a few roots on the grounds that I wouldn't be bothered to use the club much if I lived on the other side of London. Kennington, south of the Thames, rubbing shoulders with the grittiness of Lambeth and Brixton, was not where the racing crowd panted to be seen, and in fact I'd never spotted anyone locally that I knew by sight on the racecourse.

I'd come across an advertisement: 'House share available, for single presentable yuppy. 2 rooms, bath, share kit, mortgage and upkeep. Call evenings', and although I'd been thinking in terms of a flat on my own, house sharing had suddenly seemed attractive, especially after the loneliness of work. I'd presented myself by appointment, been inspected by the four others in residence, and let in on trial, and it had all worked very well.

The four others were currently two sisters working in publishing (whose father had originally bought the house and set up the running-mortgage scheme), one junior barrister who tended to stutter, and an actor with a supporting role in a television series. The house rules were simple: pay on the dot, show good manners at all times, don't pry into the others' business, and don't let overnight girl/boy friends clog up any of the three bathrooms for hours in the morning.

There was a fair amount of laughter and camaraderie, but we tended to share coffee, beer, wine and saucepans more than confidences. I told them I was a dedicated racegoer and no one asked whether I won or lost.

The actor, Robbie, on the top floor, had been of enormous use to me, though I doubted he really knew it. He'd invited me up for a beer early one evening a few days after I went to live there, and I'd found him sitting before a brightly lit theatrical dressing table creating, as he said, a new make-up for a part he'd accepted in a play. I'd been startled to see how a different way of brushing his hair, how a large false moustache and heavier eyebrows had changed him.

'Tools of the trade,' he said, gesturing to the grease paints and false hair lying in neat rows and boxes before him. 'Instant stubble, Fauntleroy curls-what would you like?'

'Curls,' I said slowly.

'Sit down, then,' he said cheerfully, getting up to give me his place, and he brought out a butane hair curler and wound my almost straight hair on to it bit by bit there and then, and within minutes I looked like a brown poodle, tousled, unbrushed, totally different.

'How's that?' he said, bending to look with me into the looking glass.

'Amazing.' And easy, I thought. I could do it in the car, any time.

'It suits you,' Robbie said. He knelt down beside me, put his arm round my shoulders, gave me a little squeeze and smiled with unmistakable invitation into my eyes.

'No,' I said matter of factly 'I like girls.'

He wasn't offended. 'Haven't you ever tried the other?'

'It's just not me, dear,' I said, 'as one might say.'

He laughed and took his arm away. 'Never mind, then. No harm in trying.'

We drank the beer and he showed me how to shape and stick on a bold macho moustache, holding out a pair of thick-framed glasses for good measure. I regarded the stranger looking back at me from the glass and said I'd never realized how easy it was to mislead

'Sure thing. All it takes is a bit of nerve.'

And he was right about that. I bought a butane curler for myself, but I took it with me for a week in the car before I screwed myself up to stop in a lay-by on the way to Newbury races and actually use it. In the three years since then, I'd done it dozens of times without a thought, brushing and damping out the effects on the way home.

Sundays I usually spent lazily in my two big bright rooms on the first floor (the barrister directly above, the sisters below) sleeping, reading, pottering about. For about a year some time earlier I'd spent my Sundays with the daughter of one of the Hobbs Sandwich members, but it had been a mutual passing pleasure rather than a grand passion for both of us, and in the end she'd drifted away and married someone else. I supposed I too would marry one day: knew I would like to: felt there was no hurry this side of thirty.