'Airport security,' said Bret sharply. 'Don't be so paranoid, Bernard.'

'I thought you'd say that, Bret. So what about my hand baggage?

What about the chatty Mr Woosnam or whatever his real name was, who just happens to get the seat next to mine and goes through my bag while I'm in the toilet?'

'You can't be sure,' said Bret.

'Sure it happened? Or sure it was the Department?'

Bret smiled. 'Bernard, Bernard, Bernard,' he said, shaking his head in disbelief. I was paranoid: the matter of my baggage was another example of my foolishness. There was nothing to be gamed from trying to pursue the subject. 'Sit back, and let's talk.'

I sat back.

'Years ago – before Fiona took a walk – I was given a job to do. Operation Hook it was called. It was designed to move some money around the globe. In those days I was always liable to get saddled with those finance jobs. There was no one else upstairs who knew anything about nuts-and-bolts finance.'

'With Prettyman?'

'Right. Prettyman was assigned to me to oversee the facts and figures.'

'Prettyman was on the Special Operations Committee with you.'

'I wouldn't make too much of that,' said Bret. 'It might have looked good on his CV but as far as that Committee was concerned he was just a glorified book-keeper.'

'But he reported back to Central Funding,' I said. 'Reported directly back to them. In effect Prettyman was their man on the Committee.'

'You have been doing your homework,' said Bret, piqued that I should have known anything about it. 'Yes, Prettyman reported back directly to Funding, because I suggested that we did it that way. It saved me having to sign everything, and answer questions, at a time when I was out of London a lot.'

'Operation Hook? I've never heard of it.'

'And why should you? Almost no one heard of it. It was very "need to know"… the D-G, me… even Prettyman didn't know all the details.'

I looked at him waving his hands about.

'Prettyman signed the cheques,' I said.

'I don't know who told you that. It's true he counter-signed the cheques. But that was just a belt-and-braces device the D-G added, to monitor spending. The cheques had the amount and the date filled in – so that Prettyman could watch the cash-flow – but he wasn't a party to the rest of it, payees and so on.'

'And suddenly Prettyman goes to Codes and Ciphers. Fiona defects.

Prettyman goes to Washington. Is it all connected in some way I don't see? What was it all for?'

'It's still going,' said Bret. 'It's still damned hot.'

'Going where?' I said.

He hesitated and wet his lips. This is still very touchy stuff, Bernard.'

'Okay.'

Another hesitation and more chewing of the lip. 'Embassy penetration.'

'I thought Ravenscroft had taken all that embassy stuff across the river. He's got a dozen people over there. What do they do all day?'

'Hook is quite different. Ravenscroft knows nothing about it.'

'So Ravenscroft and his people were moved because they were compromised?'

He shrugged. 'I couldn't say. Embassy penetration work is constantly compromised. You know that. A defector goes, and they tighten up, and Ravenscroft's life becomes more tricky for a while.' He looked at me. 'But Hook is not in Ravenscroft's class. A lot of money is involved. Hook is for really big fish.'

'I learn more from you in five minutes than I find out in the office after a year of asking questions.'

'Because I want you to stop asking questions,' said Bret. A new firmer voice now, and not so friendly. 'You're poking into things that don't concern you, Bernard. You could blow the whole show for us.' He was angry, and his angry words turned into a cough so that he had to pat his chest to recover his breath.

'Is that why I was sent here?'

'In a way,' said Bret. He cleared his throat.

'Just let me get this straight,' I said. 'You set up a lot of companies and bank accounts for this "Hook" business so you could move cash without Central Funding having any record?'

'Embassies,' said Bret. 'East European embassies. Not many people. Even I don't have the details. That's how it's run. And it makes sense that way. Because if someone in Funding had the ledgers every one of our sources could be endangered.' I looked at him. 'Big fish, Bernard…'

'And Prettyman knew about all this?'

'Prettyman knew only what he had to be told, plus whatever he could guess.'

'And how much was that?'

'Only Prettyman can answer that one.'

'And Prettyman is dead.'

'That's right,' said Bret. 'He's dead.'

'And you want me to forget the whole thing?'

'Some bloody fool of a book-keeper got his figures wrong. Panic. And suddenly it seemed like getting Prettyman back to London was the best way to sort out the muddle.'

'But now it's sorted out?'

'It was an accountant's mistake. A glitch like that happens now and again.'

'Okay, Bret. Can I go now?'

'It's no use getting tough,' warned Bret. 'This business is nothing to do with you. I don't want you prying into it. I'm asking you to back off because lives are at stake. If you're too dumb to see there's no other way.'

'Then what?'

'This is official,' he said. 'It's not just me asking you on a personal basis, it's an official order.'

'Oh, I've got that one written down and learned by heart,' I said. 'My baggage wasn't turned over because there was any chance of finding something I was hiding. I'm too long in the tooth for that one. My checked baggage was searched to show me that you were on the side of the angels. Right, Bret? Was that your idea, Bret? Did you ask London Central Operations to turn me over? Harry Strang was it? Harry's a good enough fellow. Tough, efficient and experienced enough to arrange a small detail like that. And near enough to his pension not to be tempted to confide in me that it was going to happen. Right, Bret?'

'You're your own worst enemy, Bernard.'

'Not while you're around, Bret.'

'Think it over, Bernard. Sleep on it. But make quite sure you know what's at stake.' He turned his eyes away from me and found an excuse to fiddle with the bicycle.

'Innocent lives, you mean?' I asked sarcastically. 'Or my job?'

'Both, Bernard.' He was being tough now: all that Benevolent Fund script was shredded. This was the real Bret: steely-eyed and contemptuous.

'Is this the sort of ultimatum you put to Jim Prettyman?' I asked. 'Was he his own worst enemy, until you came along? Did he give your "official order" a thumbs down so you had to have some boys from out of town blow him away in the car park?'

The shake of his head was almost imperceptible. Bret's expression had locked up tight. The gold had gone from the sunlight; he looked old and tired and wrinkled. He'd never come back and work in the Department again, I was certain of that. Bret's time had come and gone. His voice was little more than a whisper as he said, 'I think you've said enough, Bernard. More than enough, in fact. We'll talk again in the morning. You're booked on the London flight tomorrow.'

I didn't answer. In a way I felt sorry for him, doing his exercises every day, and trying to keep in touch with the Department, and even interfere in what went on there. Telling himself that one day it would all be like it was before, and hoping that his chance of a knighthood wasn't irretrievably lost.

I stood up. So it was the stick and carrot. Play ball with Bret and I even get help with the mortgage: but keep looking into things that don't concern me and I'll lose my job, and maybe lose it the way Jim Prettyman lost his job. Feet first.

Or had I misunderstood him?