We didn't talk much along the Mall except when I asked him what his Polish was like.

'I took the advanced exams before I was posted there'

I suppose he wanted me to throw him a biscuit for that.

We walked quickly because of the cold and I took him into Piccadilly to use up some of the time. The mist clung to our coats. Just after Hamilton Place a bus went by, pulling away from the kerb, and I nipped on to it, giving him room to follow.

'Are we late?'

'Not really.'

The conductor was still on the upper deck when we got off, and I took him north and went left along Curzon Street, crossing into the Park. I heard the taxi slowing from behind us before we'd reached Marble Arch; the door came open and I got in first so that he'd have to use the tip-up seat and face the rear, which was what Egerton had wanted.

'You realise,' he said to Merrick in slow modulated tones, 'that you are first and foremost a second secretary at the Embassy, just as you were before. This is very important' He had dark glasses on, which was why he wanted Merrick to face him the whole time. 'We've no concessions on the part of the Embassy enabling you to behave as anyone other than a member of Her Majesty's foreign service, careful in conduct and unimpeachable in character. Let me put it this way: we would rather go short of the information you'll be seeking than risk upsetting the Ambassador by exposing yourself to criticism on his part or to suspicion on the part of the local authorities.'

The taxi was keeping in the slow lane, rounding towards Lancaster Gate. Egerton's hands were folded on his lap, the ointment leaving dark patches on his gloves, and Merrick watched him steadily, a little disturbed at not being able to see his eyes.

'You should also bear it well in mind that there must be no exchange of confidence between yourself and the people you'll be dealing with. Confidence will be entirely on their side.