‘He dived in after a fish?’ Sherlock said, trying to imagine the scene.

‘He fell in, tryin’ to reel it in. He told me, as ah was haulin’ him out, that he would never leave the safety of dry ground again, and if that dry ground was a paved city street then so much the better.’ He paused. ‘But if you ask him, he can still tell you the feedin’ an’ swimmin’ habits of all the fish in Europe. He may have a dim view of physical exertion, but his mind is as sharp as a seamstress’s bag of pins.’

Sherlock laughed. ‘Let’s go into the reception room,’ he said. ‘Tea will be on its way.’

The reception room was just off the main hall, at the front of the house. Sherlock threw himself into a comfortable chair while Crowe settled himself on a sofa large enough to take his considerable bulk. It creaked beneath his weight. Amyus Crowe was, Sherlock estimated, probably as heavy as Mycroft Holmes, but in Crowe’s case it was solid bone and muscle.

A soft knock on the door heralded the appearance of a maid carrying a silver tray. On the tray were a pot of tea, two cups and saucers, a small jug of milk and a plate of cakes. Either Mrs Eglantine was being unusually generous or one of the staff had decided to make the guest feel welcome.

There was also an envelope, white and narrow.

‘A letter for you, sir,’ the maid said without making eye contact with Sherlock. She set the tray down on a table. ‘Will there be anything else?’

‘No, thank you.’

As she left he reached out eagerly to take the envelope. He didn’t get many letters at Holmes Manor, and when he did they were almost always from -

‘Mycroft!’

‘Is that a fact or a deduction?’ Crowe asked.

Sherlock waved the envelope at him. ‘I recognize the handwriting, and the postmark is Westminster, where he has his office, his lodgings and his club.’