‘No; those hand-made thick leather things you find in North African bazaars and in the Mediterranean ports.’

‘What else?’

‘In the case? A New Testament in French, and a yellow paper-backed novel, also in French. Both well worn.’

‘Your three minutes are up,’ said the Post Office.

Grant had another three minutes, but he got no nearer an explanation of B Seven. Apart from the fact that he had no record, either in France (the stabbing had been merely a domestic incident, it seemed) or in Britain, nothing was known of him. It was indeed typical that the one positive thing about him should be a negation.

‘By the way,’ Williams said, ‘when I was writing I quite forgot to answer your postscript.’

‘What postscript?’ Grant asked, and then remembered that he had written as an afterthought:

‘If you ever have nothing better to do you might ask the Special Branch if they are interested at all in a man called Archibald Brown. Scottish patriot. Ask for Ted Hanna and tell him I was asking.’

‘Oh, yes, of course. About the patriot. Did you have time to do anything about it? It wasn’t important.’

‘Well, as it happened, I met your reference on a Whitehall bus, day before yesterday. He says he has nothing against your bird but they would very much like to know who the ravens are. Do you know what he was talking about?’