Joe burbled on, calm and amused, until he felt her muscles begin to relax again. He released her arm. Though still avoiding his eye, Lily managed to get her voice in gear. ‘I’d like that, sir. And perhaps while we’re about it, you can tell me about Anna Petrovna’s motive. I don’t think I mentioned one?’

She was putting on her gloves when the phone rang.

In his urgent quest for roast beef and suitable accompaniments, he very nearly ignored it. Grumpily he picked up the earpiece and announced himself. He looked questioningly at Lily.

‘A package, you say? For Miss Lily Wentworth, care of this office? How big is this package? Three feet by two? That big? And heavy? I say — have you checked it for … Of course. Can’t be too careful these days. Then get two strapping fellers to haul it upstairs, will you? Use the lift. I’m just off to lunch but I can wait a few more minutes, I suppose. Tell them to get a move on, will you?’

The commander waited until the two uniformed coppers left before he approached the brown-paper wrappings of the carefully boxed parcel with a penknife. He first examined the label. ‘They made no mistake, Wentworth. It is indeed addressed to you care of my office. Were you expecting anything of this nature? Bagatelle board from Hamleys? Travelling guillotine? The missing Mona Lisa?’

She shook her head, perplexed. He clicked out the blade of his knife and began to strip away the wrapper.

After five minutes of combined effort, they stood speechless, absorbing the contents.

Sandilands was the first to regain his voice. ‘Congratulations, constable! You seem to have made a very favourable impression. A most gracious gesture — I’m sure even you will agree.’

He bent and picked up an envelope that had fallen from the wrappings. He waited while she opened it and read the message on the single sheet it contained. When she coloured and put it away he asked no question.

They continued to stare. Joe approached the painting of the Russian forest, now reset in a heavy gilt frame, and peered at it more closely. He shook his head and looked again. His fingers reached out to touch it but left off before they contacted the oil surface. He began to speak hesitantly, as though talking to himself and feeling his way through hostile territory in the dark: ‘I wonder — and you’ll tell me if you think this a fanciful idea — are we … could we possibly be … looking at a motive? Of sorts? A motive for murder? Anna Petrovna’s reason, if you can call it that — most would say “unreason” — for wanting the Prince of Wales dead? Is it staring us in the face? Am I making an unwarranted and utterly crazy assumption? If not, it’s worse than we thought.’