'And?'

'My private flying system. I'll go over with some of the boys and take care of her.'

'That's good to know. Clear the decks, that's what I like.'

'You can depend on it. Leave it to me.'

Thornton put the phone down and sat there, thinking about it. For some reason, he still felt uneasy. Now why should that be?

The following morning, the Concorde lifted off at Heathrow for Washington, and Dillon accepted a glass of champagne and sat there, thinking about it himself. In a strange way, he felt a connection with the mystery woman. It was still an incredibly intriguing situation. Why all those deaths? What was the reason?

They were no further forward, really. All the Wiley girl had done was confirm the existence of the woman, confirmed her ability to kill.

But why, why, why? That was what really fascinated him and there was no answer.

It was the following morning, round about the time Dillon was reaching Washington, that Thornton, trawling on Helen Lang's whereabouts, was stunned to note that she was booked to land at Westhampton Airport at Long Island in her private Gulfstream the following afternoon. He sat there, thinking about it. The question was why, and the obvious answer was Chad Luther's party. He accessed the right side of the computer again, looked for Luther's guest list and there she was. He thought about it, then phoned Barry again.

'Lady Helen Lang. She's attending a big fat cat party tomorrow night on Long Island, so don't look for her at home.'

'I can wait,' Barry said. 'Don't worry. She's history.'

Lady Helen, at the South Audley Street house, went into the kitchen and put the kettle on, as Hedley took the bags upstairs. He appeared as the kettle boiled and she made tea.

'Anything you want me to do?'

'Not really. We'll leave from Gatwick in the morning, land in Long Island in the afternoon, and carry on to Chad Luther's place.'

'Are we staying over?'

'I'd have thought I might need to leave in a hurry.'

Hedley refused to be drawn. 'Whatever you say, Lady Helen,' and he turned and went out.

Ferguson, at his desk, rang through to Hannah Bernstein and called her into his office. 'How are you getting on with your fresh computer investigation?'

'I'm still looking, sir. The thing I can't understand is that we know a great deal about the Sons of Erin and what they got up to, but we don't have any information on the specific act that would explain a personal vendetta on the part of this woman.'

'So you agree with Johnson and Parker about that.'

'Oh, yes, sir. You spend years on the street, sir, you investigate one rotten crime after another…"

'And you get a nose for it, a copper's nose?'

'Exactly, sir. Unlike in an Agatha Christie novel, when I visit the scene of the crime and take a look at who is involved, in most cases I can pick out who it is almost straightaway.'

Ferguson smiled. 'I'm with you on that, Chief Inspector, so what does it leave us? What does that fine Cambridge-educated mind tell you?'

'That central to all this is Jack Barry, but all the computer tells us is his background of offences. No mention of his connection with the Sons of Erin, or indeed any mention of the Sons of Erin, and that doesn't make sense, sir.'

'And your conclusion?'

'It's not there because somebody didn't want it there.'

'The Secret Intelligence Service?'

'I'm afraid so.'

Ferguson smiled. 'You know, you really are very good, my dear. It's time Special Branch elevated you to Detective Superintendent. I must speak to the Commissioner at Scotland Yard.'

'I'm not too worried about elevation, Brigadier. There's a black hole that needs filling. What do we do?'

'What would you suggest?'

'I think you should see the Deputy Director of the Security Services, sir, and as our American colleagues would say, I think you should kick ass.'

'Oh dear, Simon Carter wouldn't like that, but I think you're absolutely right. Phone him and tell him to meet us at the Grey Fox in St James's in exactly one hour.'

'Us, sir?'

'I wouldn't dream of depriving you of the pleasure of putting one of those Manolo Blahnik high heels in him, Chief Inspector.'

Hannah smiled. 'A pleasure, sir.'

The Grey Fox was one of several upper-class pubs in the vicinity of St James's Palace. It was two-thirty, most of the lunch trade running out, the place almost empty. Ferguson and Hannah took a secluded booth.

'Gin and tonic, Chief Inspector?'

'Mineral water, sir.'

'What a pity. Personally, I'll have a large one.'

The barmaid brought their drinks and almost immediately Simon Carter came in. His raincoat was wet and he shook his umbrella, obviously not in the best of moods.

'Now what in the hell is this, Ferguson? The Chief Inspector here actually threatened me, the Deputy Director of the Security Services.'

'Only when you said you were too busy to come, sir,' Hannah told him.

He took his coat off, called for a whiskey and soda and sat down. 'I mean, threatening me with prime ministerial privilege. Not on, Ferguson.'

'My dear Carter, you don't like me, and if I thought about you at all, I probably wouldn't like you, but we're into serious business here, so listen to the Chief Inspector.'

He drank his gin and tonic, waved for another and sat back.

She went through everything, the Tim Pat Ryan shooting, the extermination of the Sons of Erin, Jack Barry, Jean Wiley's statement. It left Carter stunned.

'I've never heard such nonsense,' he said weakly.

Ferguson shrugged. 'Good, that clears the decks.' He turned to Hannah. 'What time was our appointment with the Prime Minister?'

She lied cheerfully. 'Five o'clock, sir, though he can't give you long. He's due at the House this evening.'

Ferguson started to rise, and Carter said, 'No, just a moment.'

Ferguson subsided. 'What for?'

It was Hannah Bernstein, the copper as always, who said, 'Are you able to assist us in our inquiries, sir?'

'Oh, don't give me all that police procedural nonsense.' He called for another Scotch and turned to Ferguson. 'I haven't said a word about this. I'll always deny it.'

'Naturally.'

'And I want your Chief Inspector's word that this stays with the three of us. If she can't guarantee that, out she goes.'

Ferguson glanced at Hannah, who nodded. 'My word on it, Brigadier.'

'Good, let's get to it,' Ferguson said.

'We've never got on, my organization and yours, Ferguson. Too damned independent.' He shook his head. 'Prime Minister's private army. Never liked that. People should be accountable and you do what you damn well like.'

'And you don't, sir?' Hannah said gently.

Carter sipped his Scotch. 'There are things we never told you, Ferguson, because we didn't trust you, just like there are things you've never told us.'

Ferguson nodded to Hannah, who said, 'You know the facts, sir. I'm a police officer, I'm trained to look for answers, and what I see here is that one individual has taken care of all the victims here, and there has to be a reason for it. Something very bad happened, and I think you know what it was, and I think you had it erased from the computer memory and expunged the records.'

'Damn you!' Carter told her.

'Barry,' Ferguson said. 'It has to be him behind all this. Tell us now.'

Carter took a deep breath. 'All right. When the peace process began, we were told to be nice to our American cousins, pass them any useful information about what was happening in Ireland.'

'I know,' Ferguson said.

'Then we began to realize that stuff we'd passed to the White House was ending up in IRA hands. The culmination was a shocking atrocity which we found later was committed by Jack Barry and his gang. An entire undercover group, some of our best officers, was taken out.'