Sandilands went straight to Miss Jameson’s room across the corridor and stayed there for a few minutes before returning to his own office, where he found Lily closing the file and laying down her pencil.

She looked up and gave him a friendly smile. He swept off his hat, offered a clean-cut profile and asked: ‘Well, what do you think of Raoul’s handiwork?’

‘Raoul is an artist, sir. He could find a position with the finest embalming parlour in the land.’

He grinned. He decided he could get along with her cheerful lack of deference. ‘Well, how’s it going with the Dedham affair? Reached any conclusions?’

‘It’s a bit early for conclusions, sir. There’s a lot of evidence still to come in. But I have one or two thoughts.’

‘Go on.’

‘There’s something not quite right with all this. Someone at the centre of it is telling you naughty lies.’

Joe had decided as much himself in the early hours. ‘You think so? But it’s perfectly straightforward, isn’t it? A shooting occurred and the killers were apprehended, guns still smoking in their hands. And we have a confession from both of them.’

Lily produced Hopkirk’s sketch. ‘Where exactly had these men concealed themselves to lie in ambush? They must have been laid up there for ages. No one could have predicted to the minute — or even the hour — when the Dedhams would fetch up home at the end of their evening. I don’t suppose they knew themselves. And these thugs weren’t just passing by. This was not their territory. They wouldn’t have been comfortable here.’

‘And regular police patrols would have picked up — at the very least recorded — any doubtful strangers,’ Sandilands confirmed.

‘According to Lady Dedham the cab driver checked the shrubs nearest the house before she alighted and gave her the all clear. She had her wits about her but tells us that she too saw nothing of concern near the house. And yet, less than a minute later the gunmen emerged from these very bushes …’ She pointed with the end of her pencil. ‘Did the cabby look properly? Was he mistaken? Or was he lying and leading them into a trap?’

‘What a pity he’s unable to speak for himself.’

‘Is it known, sir, how they engaged his services? How they came to be riding in that particular cab?’

Joe noted her foresight. ‘Yes. I asked Lady Dedham. All above board. The cabs were lined up outside the hall when the meeting turned out and the Dedhams took the next in line. They weren’t the first and they weren’t the last out. Luck of the draw.’

‘Look — what do you think of the possibility of distraction, sir? Deliberate or accidental?’ Her pencil moved south to the opposite side of the road. ‘There’s a sort of little green area over here … it’s hard to envisage what’s on offer from a map …’

‘Shrubs,’ Joe supplied. ‘I skulked around in there myself. You could hide a couple of quiet men in there for hours.’

‘Righto. Let’s picture them hiding here while the cabby does his reconnaissance and safely unloads Lady Dedham. Then we imagine him walking back to the taxi to assist the admiral … it’s at that moment that the men run across the road and hide in the bushes near the doorstep. A diversion could well have been staged then, don’t you agree? Though the circumstances are not yet perfectly clear.’

‘Yes. The arrival of the next fare. The young lady who barged in to commandeer the cab.’

Lily read from her notes: ‘Miss Harriet Hampshire, giving an address in Park Lane.’ She paused, her brow furrowed in thought. ‘It rings a bell with me … Is this one of the houses near Pinks Hotel, sir?’

Joe nodded.

‘And Miss Hampshire claims to have been in Melton Square, visiting a friend. At least that’s what she told Superintendent Hopkirk.’

‘I saw her,’ he said. ‘Briefly before they drove her home. Stunner! She’d certainly have diverted the admiral’s and the driver’s attention. Yes, two dark-clad men, profiting from a distraction, could have got across the road to the forward cover position without being spotted. And they were wearing rubber-soled shoes. In any case, any sound would have been masked by the noise of the taxi engine, which had been left running.’ He heaved a sigh. ‘The admiral dismissed the cabby, and strolled down to his front door. The moment he stood on the doorstep, off guard and backlit by the hall lights, they struck.’

‘I’m wondering why the cabby didn’t set off at once, sir?’

‘Waiting — as he’d said he would — to make sure all was well?’ Sandilands suggested. ‘Some sort of argy-bargy with the girl? Checking directions?’

He broke off and then said, with decision: ‘But look here — that’s enough desk work. Before we go to the hospital, or the jail, why don’t I take you out to look at the scene? Cassandra — Lady Dedham — is expecting me to pay another visit. We’ll take a staff car and go and see whether, in the cold light of day, she’s remembered anything more of significance, shall we?’

And time to put the girl at the fourth — and perhaps the hardest — hurdle.