Both mother and daughter looked as if they agreed with him but Mercer, smiling round clenched molars, said with surprising bitterness, 'You will do what I ask or accept the consequences.' And Sheridan looked furious but also afraid.

They had spoken as if I weren't there, which in a way I wasn't, as other passengers were moving round me, all asking the same questions. 'Anywhere, madam. Anywhere, sir,' I said, and 'I'm afraid we can't serve alcohol before departure.'

Departure came from one instant to the next, without any whistles blowing, horns sounding or general ballyhoo. One moment we were stationary, the next sliding forward smoothly, the transition from rest to motion of a quarter of a mile of metal achieved as if on silk.

We emerged from the shadow of the station into the bright light of noon, and Daffodil Quentin under her sunburst of curls made an entrance from the dome car end, looking about her as if accustomed to people leaping up to help.

'Where do we sit?' she asked, not quite looking at me, and I said, 'Anywhere, madam. Wherever you like.'

She found two seats free not far from the Lorrimores and, putting herself on one chair and her handbag on the other, said with bonhomie to the elderly couple already occupying the table, 'I'm Daffodil Quentin. Isn't this fun?' They agreed with her warmly. They knew who she was: she was yesterday's winner. They started talking with animation, like almost everyone else in the car. There was no cool period here of waiting for the ice to break. Any ice left after the previous day's racing had been broken conclusively in the scenes out in the station, and the party had already gelled and was in full swing.

Emil beckoned me towards the kitchen end, and I went up there into the small lobby with a serving counter, a space that made a needed gap between the hot glittering galley and the actual dining area. The lobby led on the left to the kitchen and on the right to the corridor to the rest of the train, along which desultory passengers were appearing, swaying gently now to the movement of gathering speed.

Behind the counter, Emil was opening bottles of Pol Roger. Oliver and Cathy were still taking glasses from a cardboard container and arranging them on small trays.

'Would you mind polishing some of these smeary glasses?' Emil said to me, pointing at a trayful. 'It would be of great help.'

'Just tell me,' I said.

'Polish them,' he said.

'That's better.'

They all laughed. I picked up a cloth and began polishing the tall flutes, and Filmer emerged from the corridor and crossed into the dining room without glancing our way.

I watched him walk towards Daffodil, who was waving to him vigorously, and take the place saved by her handbag. He had his back to me, for which I was grateful. Prepared for the closeness of him, I was still unprepared, still missing a breath. It wouldn't do, I thought. It was time for a bit of bottle, nor for knocking knees.

Every seat in the dining car filled up and still people were coming. Nell, arriving, took it in her stride. 'Bound to happen. All the actors are here. Give everyone champagne.' She went on down the car, clipboard hugged to her chest, answering questions, nodding and smiling, keeping the class in order.

Emil gave me a tray of glasses. 'Put four on each table. Oliver will follow you to fill them. Start at the far end and work back.'

'OK.'

Carrying a tray of glasses would have been easier if the floor had been stable but I made it to the far end with only a lurch or two and delivered the goods as required. Three or four people without seats were standing at the far dome car end, including the actress Angelica. I offered them all glasses as well, and Angelica took one and went on bellyaching to all around her about how Steven had let her down and she should never have trusted the louse, and it was a tribute to her acting that there was a distinct drawing aside of skirts in the pursed mouths of those around her who were fed up with hearing about it.

Oliver, on my heels, was delivering them solace in Pol Roger's golden bubbles.

I came with acute awareness to the table where Filmer was sitting with Daffodil and, careful not to look directly at either of them, put my last four glasses in a row on the tablecloth.

At once Filmer said, 'Where have I seen you before?'

About fifty conclusions dashed through my head, all of them disastrous. I had been so sure he wouldn't know me. Stupid, arrogant mistake.

'I expect it was when we were over in Europe and went to the Derby Eve dinner in London,' the elderly woman said. 'We sat at the head table… We were guests of dear Ezra Gideon, poor man.'

I moved away sending wordless prayers of thankfulness to anyone out there listening. Filmer hadn't even glanced at me, still less had known me. His head, when I'd finally looked at him, was turned away from me towards his companions, as was Daffodil's also.

Filmer's own thoughts must anyway have been thrown in a tangle. He was himself directly responsible for Gideon's suicide, and now he found himself sitting with Gideon's friends. Whether or not he felt an ounce of embarrassment (probably not), it had to be enough to make him unaware of waiters.

I fetched more glasses and dealt some of them to the Lorrimores who were an oasis of silence in the chattering mob and paid me absolutely no attention: and from then on I felt I had indeed chosen the right role and could sustain it indefinitely.

When everyone was served, Zak the investigator appeared like a gale-force wind and moved the mystery along through Scene Two, disclosing the details of the attempted kidnap of one of the horses and leaving a tantalizing question mark in the shape of which one? To the amusement of the audience, he quizzed several of the real passenger owners: 'Which is your horse, sir? Did you say Upper Gumtree?' He consulted a list. 'Ah yes. You must be Harvey Unwin from Australia? Do you have any reason to believe that your horse might be the target of international intrigue?'

It was skilfully and entertainingly acted. Mercer Lorrimore in his turn and with a smile said his horse was called Voting Right, and no, he'd had no advance notice of any attack. Bambi smiled thinly, and Sheridan said in a loud voice that he thought the whole thing was stupid; everyone knew there hadn't been any goddam kidnap attempt and why didn't Zak stop messing around and piss off.

Into a gasping horrified silence while Mercer struggled for words, Zak smiled brilliantly and said, 'Is it indigestion? We'll get you some tablets,' and he patted Sheridan compassionately on the shoulder.

It brought the house, or rather the train, down. People laughed and applauded and Sheridan looked truly murderous.

'Now, Sparrowgrass,' Zak said, consulting his list and very smoothly carrying on, 'who owns Sparrowgrass?'

The elderly gentleman sitting with Filmer said, 'I do. My wife and I.'

'So you are Mr and Mrs Young? Any relation to Brigham? No? Never mind. Isn't it true that someone tried to burn down the barn your Sparrowgrass was stabled in a month ago? Could the two attacks be linked, would you say?'

The Youngs looked astounded. 'How ever did you know that?'

'We have our sources,' Zak said loftily, and told me afterwards his source was the Daily Racing Form, busily read recently for background help with his story. It impressed the passengers most satisfactorily.

'I'm sure no one's trying to kidnap my horse,' Young said, but with a note of doubt in his voice that was a triumph for Zak.

'Let's hope not,' he said. 'And finally, who owns Calculator?'

The actors Walter and Mavis Bricknell put up their hands in agitation. 'We do. What's wrong with him? We must go at once to make sure. The whole thing's most upsetting. Have you proper guards now looking after the horses?'