'Thought I'd kind of steal up on you.'

K -- 15 was a hands -- on but much -- used Soviet code that the people in Codes and Cyphers at the Bureau had been trying to break for three years. I knew it had been done but I'd thought it was in London.

'Another egg?' Jane asked.

'If you can spare one.'

'No problem,' she said. 'Blackmarket.'

I didn't know when I was going to eat again. There'd been two signals from Control earlier this morning but Zymyanin still hadn't made contact. It was just gone eight, and the clothing shop wouldn't open until nine. 'Even if then,' Jane had said. 'We might have to bash at the back door.'

'You worked on it at the embassy here?' I asked her. On K -- 15.

'Yes. I'd be an infant prodigy in maths, if I were an infant. When I was six I used to finish Dad's crossword puzzles for him when he was at the office, made him furious. And they were in The Times.'

At the scrubbed pinewood table she said, 'Ketchup? I also created Mystere.' she watched me for my reaction.

'Did you, now.'

Mystere was also a hands -- on code, non -- computerized, and C and C had brought in a man from the Foreign Office to try breaking it. He hadn't managed it so far but when he did we'd destroy it, because if he could break it so could the Soviets, or someone else.

'I got it from my typewriter,' Jane said.' Or that started me off. I use a Canon AP810 -- III, and I was changing the ribbon when I noticed the characters on the old one. It's a wide ribbon and they're not in a single -- line row, it prints three characters vertically, shifts -- wait a minute --' she reached for her pad and got a pencil --' it prints three characters vertically downwards, then shifts one space to the right and prints upwards again, three --' she glanced up at me --' am I being an infant prodigy all over you?'

'I've worked on codes,' I said. 'I'm interested.'

'All right. Three down, then shift, three up, shift, three down again, like this. And if you read it like that, it makes sense, but we always read in a single line from left to right, and that looked like gibberish, and it suddenly struck me -- 1 was looking at a code.' she put the pencil down and bit on some toast and munched it. 'But if we, say, typed the words, oh, I dunno, "if you like", the "y" comes at the bottom of the first vertical and the "o" comes at the bottom of the next one, and there aren't too many ordinary words beginning with "yo" except for "you" -- and you start getting the drift. So at the top and bottom of every vertical I inserted a blind character to break the rhythm, and that was much nicer.' she sat back and looked at me. 'Had enough?'

'No.'

. ' Glutton for punishment. So I 'm reading three horizontal lines of code and I'm not picking up clues from the verticals because of the blinds. At that stage it would have taken a bright teenager maybe half an hour to break, so I threw in a reverse -- direction read -- out and put it on the standard grid and went for three -- character alphabetical substitutes and froze it. Mystere!' she shook her pony -- tail. 'God, don't tell the man in London.' Her eyes were suddenly deep, their colour darkening. 'Or anyone.'

'I'm offended,' I said.

'Sorry.' she drew a breath, let it out. 'I want that one to run for ever.'

'It probably will.'

'I shouldn't think so. I mean, basically it's terribly simple. But it touched my funny -- bone to think of all those typists out there -- it's probably the same with any typewriter, not just a Canon -- using the basis for Mystere when they're ordering another consignment of paperclips or whatever. More toast?'

'No, I've finished. Are you working on anything new, at the -- 'then the phone rang and I went over to it while Jane cleared the table.

'We've found Zymyanin.' It wasn't Medlock's voice; this was the man on the day shift, and I recognized him because he'd been on the board for Solitaire, name was Carey. 'He's still in Moscow.'

'He made contact?'

'No. We had him traced -- he went to his base in Lenin Prospekt.'

'He's worked with us before?'

In a moment, 'He's Bureau, but rather a lone wolf.' He didn't query the fact that I hadn't been briefed on Zymyanin, didn't want to tread on any toes. 'We've got a watch on him, and when he moves, we'll let you know. We think he's frightened, you see.'

'Yes.' It was possible that Jane didn't know Zymyanin, and couldn't have briefed me. Croder would have assumed I could trust him to know that the Soviet was reliable. But it made me uneasy: I didn't much care for lone wolves in a sensitive field like Moscow.

'But he should come round, in good time. If he doesn't ask for a rendezvous you'll have to make your own way. We'll keep you posted as to his movements. Don't leave the phone.'

I told him I'd got to go and find some clothes.

'Okay, but there's an answering machine, right?'

'Yes.'

'Keep as close as you can, though, in case he suddenly takes off somewhere.'

I said I'd do that.

'Any questions?' Carey asked me.

'No, but you can look after a couple of things for me. Was Hornby married?'

'Yes.'

'Send some flowers, will you?'

'How much for?'

'Oh, twenty pounds.'

'Name on the card?'

'Put anything. She doesn't know me.'

'Will do.'

'And tell Accounts we owe the Romanian Ministry of Agriculture for a sack of Grade A rye grain, 150 lbs.'

There'd be a squeal from that acidic old bitch in the counting house because she's always touchy about passing anonymous funds into Moscow without any explanation, but the rule is that if we damage any property we've got to report it and it's got to be paid for, and in any case this was nothing, the last thing I'd stuck Accounts for was a smashed Mercedes.

'Anything else?' Carey asked me. I said no and we shut down.

This was at 8:44.

* * * It was mid -- afternoon when London came through with instructions.

Medlock was back at the board.

'Zymyanin has booked out on the Rossiya to Vladivostok. Please stand by for Chief of Signals.'

Jane had been typing a report for the embassy, and stopped, leaving the room quiet. The sky in the high narrow window was already darkening toward nightfall even at this hour. The snow had eased off soon after we'd got back from the clothing shop.