Harry spread rugs on the grass and Rose and Daisy helped Becket lift out dishes, glasses and food from the hamper.

They drank champagne and ate delicacies from Fortnum and Mason such as grouse in aspic while the river chuckled past over the willow trees and the moving leaves of the other trees around their green oasis on the river bank sent flickering shadows over their faces.

When the meal was finished, Harry said to Rose, ‘Walk a little with me. I have something for you.’

He helped her to her feet and they strolled away through the trees watched by the ever-hopeful Becket and Daisy.

He finally stopped and pulled a little jeweller’s box out of his pocket. ‘I should have bought you a ring before this. Most remiss of me.’

Rose opened the box. A large and beautiful diamond set in white gold glittered up at her, throwing rainbow prisms of light across her astonished face.

‘This is too much,’ she said. ‘I cannot accept it. It is not as if we are really engaged.’

‘I wish you would keep it as a memento of all our adventures. The diamond was a present to me from someone in South Africa.’

He took her hand in his and slid off the little engagement ring she had bought herself. Rose stood frozen as he slid his ring onto her finger. ‘Please take it . . . Rose.’

She suddenly smiled up at him. ‘Yes, I will. Thank you. I think we could be friends after all.’

He tucked her arm in his and they walked on. ‘You must admit we are a very unusual pair. The misfits of society. Just like Kerridge.’

‘Is Mr Kerridge a misfit?’

‘Indeed he is. He would like to see all the aristocracy strung up from lamp-posts with himself manning the barricades at some people’s revolution.’

‘Why? We have always been kind to him.’

‘I can see his point. Any time he has to interview one of us, he is threatened with losing his job. “My friend the Prime Minister will hear of this.” That sort of thing.’

‘Mostly I accept my position in life,’ said Rose slowly. ‘One is immured from the sufferings of humanity. But when I rescued Miss Friendly, I was almost ashamed of myself for having chosen one easily grateful genteel lady who will not cause me any trouble when there are others, hundreds and thousands, even more deserving.’

‘I felt the same way when I rescued Phil. Did I tell you about Phil?’

Rose listened while he described his visit to Bermondsey. Then she said, ‘When I reach my majority I will have my own money. I wish to set up a charity.’

‘Let me know,’ said Harry, ‘and I will contribute.’

They walked back to join Becket and Daisy. Becket was making tea. Rose showed Daisy her ring and Daisy glanced at Becket, who sent her a covert wink.

They were all happy and at ease with each other when they finally drove back to London.