‘Two things, if you will be so good; to give me, first, a list of your West End branches and second, a note to your managers, asking them to assist me.’

‘I will do both with pleasure.’

Ten minutes later Tanner reached the first branch. Here he saw the manager, presented his note, and explained his business. The official was extremely civil and brought the Inspector to each of the salesmen in turn. All gave him their careful attention, but none could recall Austin Ponson nor recollect the sale in question. With courteous thanks Tanner took his leave.

The second branch was not far away, and here the Inspector made similar inquiries. But here again without result.

Recognising that his quest was going to be tedious, he engaged a taxi and settled down to work systematically through the list. Progress was slow, and it was approaching six o’clock by the time he had reached the ninth branch. But here, just as he had decided he would visit no more that evening, he had some luck.

In this shop, the second salesman he spoke to instantly recognised Austin’s photograph, and recollected the purchase of the shoes.

‘Yes,’ he said, ‘I remember the man perfectly. What drew my special attention to him was the very peculiar way he conducted the purchase. He came in and said he wanted a pair of Glimax B10735 over 789647S. He did not look at the shoes I brought him, except to check the number. I remarked that few gentlemen knew what they wanted so precisely as that, and he said he had had a pair of the same before which had suited him, and he simply wanted to replace them.’

‘About what time was that?’

‘Shortly after four, I should say.’

‘And did he give his name?’