On her way back to Camden Town, Miss Jubbles comforted herself with the thought that Harry would notice the absence of his lovely rose-decorated cup.

The next time Ailsa served Harry tea in a cup embellished with lilacs, he did not notice the difference.

Rose would not admit it to herself but she was more determined than ever to find out the identity of the murderer as a way of seeing Harry again.

‘I think perhaps I should encourage Tristram,’ she said to Daisy.

‘You’re never thinking of marrying him!’

‘No . . . although it has crossed my mind that I would not have so restricted a life were I married.’

‘Then what happens if you fall in love? You’re not the kind to have an affair.’

‘I don’t think I shall ever fall in love. Gentlemen are so . . . weird.’

‘So why are you going to encourage that bleeder?’

‘Language, Daisy!’

Daisy sighed. ‘I mean, why?’

‘Because he was Freddy’s best friend. We know little of Freddy’s habits or where he went apart from to these boring social affairs and to his club. He might have had a mistress and set her up in one of those places they set up mistresses, like St John’s Wood, and the blackmailing stuff could be hidden there.’

‘Why not tell the captain your idea? It’s his job.’

Rose set her lips in a firm line. ‘It is my idea and I will follow it through.’

In the weeks that followed, Harry had gone back to his usual detecting duties of finding lost dogs and covering up scandals. To his surprise, none of these scandals seemed to disturb his hard-working secretary. Miss Jubbles had smelt of rosewater. Ailsa smelled of peppermint, which seemed to be her only weakness.

Harry would have been amazed had he known that she despised society as heartily as Kerridge and admired her employer for having chosen to work for a living.

One day when Harry was out, Brigadier Billy Handy called. ‘Came to see how you were settling in,’ he said.

‘Very well. Thank you for the recommendation.’

‘Need to be discreet in this business. But you’re used to that, hey?’

‘Exactly,’ said Ailsa.

‘Mind you, it’s funny work for a baron’s son, albeit a younger one. He should find himself an heiress. Funny. I thought he and that beauty, Lady Rose, might have got hitched. No sign of that?’

‘None whatsoever.’

When he had gone, Ailsa slid open the bottom drawer of her desk and took out a squat bottle of gin. She poured a strong measure into a teacup and knocked it back. She heard footsteps on the stairs and put the gin bottle away, took out a little bottle of peppermint essence and swallowed some, then darted to the cupboard and hid the teacup.