‘He’s playing with one of his friends across the road. He starts elementary school in a couple of weeks. Look, Philip, it’s always a great pleasure to see you, but I’m pretty sure you’re here with some purpose in mind.’

‘Are you suggesting I only ever arrive when I want a favour?’

She raised an eyebrow.

‘Well, I must confess that often is the case. I will make amends one day and simply turn up with a motive-free picnic. Anyway, you are as always extremely perceptive. Lydia the practical poet – a wonderful combination.’

‘And you can stop buttering me up, because it won’t work. If you have a favour to ask, just ask it.’

‘Which brings me neatly to Mr Borisov here. Despite his passable English, you will probably have observed from his accent that he is Russian.’

‘Carry on.’

‘He has defected from the Soviet zone in Berlin to seek asylum in Britain.’

Lydia frowned. ‘Why would he defect? I thought we were allies.’

‘We are. But there are tensions and they’re growing. Not that that is the reason he felt obliged to leave Russia. He believed he was marked down for execution by Comrade Beria and so, understandably, he hoped to avoid a bullet in the head. As you might imagine, he brings with him a wealth of information of life inside the Kremlin. Now he needs a safe house for a very short time.’

‘What does that have to do with me?’ she demanded, knowing very well what it meant.

‘Well, you see, it was Tom who got him out of the Soviet zone.’

‘Let me guess: you’re suggesting that you want him to stay here with me and Johnny.’

‘I confess that was the idea.’

‘Oh no, Philip, that’s really not on. Anyway, I happen to know that the secret service has its own safe houses. In fact, I seem to recall there’s one not far from here, used by Five. You’ve used it yourself.’

Eaton and Borisov exchanged a meaningful glance. ‘This is difficult for me to admit, Lydia,’ Eaton said, ‘but I have to tell you that we have a problem. I can’t use any of our safe houses for one simple reason – they’re not safe. It seems we have at least two traitors, one in Five, one in Six. It is possible that there are more.’

‘Well, why don’t you charge them?’