'If you say so.'

'One final point. The undercover group wiped out by Jack Barry three years ago. Major Peter Lang and company? You made no mention of that to Chief Inspector Bernstein.'

'Because she didn't ask me. The facts are there on the computer for all to see. However, there has never been any suggestion that Barry and the Sons of Erin had anything to do with that affair. Trawl all you like, Ferguson, there is no such file. Now, is there anything else? I'm a busy man.'

'Not really. I'll tell the Prime Minister you've been as cooperative as usual.'

Carter frowned. 'You mean to involve the PM in this matter?'

'You, of all people, know my unique position in that respect. The Prime Minister's private army, isn't that what you call my department?'

'Damn you!' Carter exploded, and turned on his heel.

'There you go then,' Dillon grinned. 'What next?'

'I've already fixed a meet with the Prime Minister this afternoon,' Ferguson said. 'I'll take you in with me so that he can share your input, Blake. You, Dillon, will stay in the car as usual.'

Dillon smiled at Blake. 'Nothing changes and I know my place.'

Back at the Ministry of Defence, they found Hannah Bernstein still at the computer. 'Anything to report?' Ferguson asked.

'I did come across one interesting thing, sir. According to various sources, the Security Services have been less than generous over the past two yean with sensitive information having to do with Irish operations as regards our American friends. The word was that such material did seem to end up in the hands of Sinn Fein on a regular basis.'

'So what's been happening?' Ferguson asked.

'Oh, the general flow hasn't stopped, but it would seem that the quality of the material has left a great deal to be desired. Frankly, it's been the kind of stuff you could get from the political page of the better newspapers. A few titbits thrown in occasionally

Dillon cut in. 'But no more details of undercover operations?'

'So it would appear.'

'But if this was an official SIS attitude,' Blake said, 'wouldn't you have known about it?'

'I'm the last person they'd tell,' Ferguson said. 'They've always hated my privileged position with the Prime Minister. Placed every obstacle in my way, offered as little cooperation as they've been able to get away with.'

'I know the feeling,' Blake said. 'I have my own problems with the CIA and the FBI.'

'So what we're saying is that Carter and his people knew about what happened three years ago,' Dillon said. 'Maybe not straight away, but at some stage.'

'I'd say so.' Ferguson nodded and turned to Hannah. 'Put your fine Cambridge mind on it, Chief Inspector.'

'We have two facts that are certain, sir. Something made them start treating our American friends with enough suspicion to offer innocuous material and disinformation. I'd say at an earlier stage they probably heard about what happened, but decided it was simply beyond proof.'

'And the second fact?'

'That there isn't a file, at least not now. If the Deputy Director says so, I believe him.'

'Do you?' Blake asked Ferguson.

'Oh, yes, it fits. They play their own games, you see. With the peace process so important, they would decide they didn't want to give the Prime Minister a problem, because that would have involved the President and given him a problem. It would have also brought me in and involved you.'

'The bastards,' Blake said.

'Yes, but they weren't losing anything if they were sending your people useless information,' Ferguson said. 'We dealt with the Nazis during the Second World War in the same way, conned the Abwehr rotten.'

'All the same, it makes you wonder who's running the country,' Dillon said.

Hannah nodded. 'So what do you intend?'

'To see the Prime Minister. I've no choice, just as Blake has no choice. President Cazalet will expect a report on the Barry affair and I can't see Blake telling him less than the whole truth.'

'Exactly,' Blake agreed.

'And the question of the SIS involvement, sir?' Hannah asked.

'But there isn't one. No file, no knowledge of anything untoward. Astonishment at McGuire's story and delicate hints that it's all rubbish.'

'So that's it?' Hannah said.

'Not at all. I'll see the Prime Minister, bring him up to date, and from now on, handle this whole business my way.' 'And God help Simon Carter,' Dillon said.

The Daimler was admitted through the security gates at Downing Street. Ferguson said, 'I don't think we'll be long.'

'Sure and I'm used to waiting when we come to this place.' Dillon grinned at Blake. 'I'm useful when they need a hired gun, but an embarrassment to the great man in there all the same.'

'I'd read The Times if I were you. It's very instructive,' Ferguson said, and got out, followed by Blake.

The policeman saluted, the door swung open and an aide smiled a welcome. 'Brigadier, Mr Johnson. The Prime Minister expects you.'

He took them upstairs past the portraits of all the previous Prime Ministers, then along a corridor, knocked briefly at the study door and opened it. The Prime Minister was sitting behind his desk, stood up and came round to shake hands with Ferguson.

'Brigadier.'

'Prime Minister. When you came to office, we discussed the peculiar circumstances of my position with you. Do you recall my mentioning that the President had a similar outfit working for him?'

'The Basement?'

'Yes, Prime Minister. This is Blake Johnson, who runs it.'

The PM shook hands with Blake. 'Be seated, gentlemen. You did indicate this was a matter of grave importance.'

'Very much so,' Ferguson said.

'Then tell me.'

When Ferguson was finished, the Prime Minister sat there, frowning. 'An incredible story. What happens next?'

' Mr Johnson will have to report to his President. I would suggest he does that when he gets back to my office.'

'I agree. As it happens, I have to speak to the President on matters concerning the peace process in Ireland later this evening. I'll discuss this affair with him and make it clear I have complete faith in you and Mr Johnson.'

'And what about the position of the Deputy Director of the Security Services?'

'What position?' The Prime Minister's face was calm. 'They know nothing, Simon Carter was definite on that score. "No file" was his phrase. Good. This would appear to be exactly the kind of thing my predecessors expected you to handle, Brigadier, so handle it.'

'You have my word, Prime Minister.'

He and Blake stood, the door opened as if by magic, and they were escorted out.

As it happened, Blake was unsuccessful in trying to speak to the President. He was finally routed to the chief of staffs secretary, who told him that the President was in Boston making a speech. Afterwards he was going down to his house on Nantucket for a three-day break. Next, Blake spoke to his secretary, Alice Quarmby, and because he was using the Codex Four line, he was able to speak openly.

'I was worried about you,' she said.

'You should be. That bastard Barry slipped the net, but he almost got me. This Sons of Erin outfit he runs – he spoke of a New York branch. Check it out and see what you can find.'

'Right away.'

'I need to get back fast, so see if there's anything military leaving the UK later today.'

'I'll call you back.'

In Ferguson 's office they had a final discussion. It was Hannah who stated the obvious. 'There's nothing more we can do over here.'

'Yes, it's up to you, old son,' Dillon said. ' New York branch of the Sons of Erin.' He laughed. 'Sounds like one of those Irish theme pubs.'

Blake frowned. 'You know something, that's not a bad idea.'

'Which still leaves you with the mystery of the White House,' Hannah told him. 'Like one of those Agatha Christie murder mysteries.'