When the doctors had finished with Emerson Merckle a nurse took Kathy in to see him. His left arm was in a sling, he had a large dressing on his forehead and he looked groggy.

‘I’m Detective Inspector Kathy Kolla from the Metropolitan Police, Mr Merckle. How are you feeling?’

He lifted his eyes to her with a bleak expression, unable to find the words to answer that. ‘The other officer said it was possible that Nancy was deliberately killed. Tell me that isn’t true.’

A retired businessman or professional, Kathy guessed.

‘It sounds improbable, but several witnesses interpreted what happened in that way. We’re doing all we can to find the man who ran into you.’

‘I thought that nothing could shock me any more. How wrong I was.’

‘Can you tell me anything about him?’

‘Not a thing. One minute I was walking along the street, the next I was face down on the sidewalk. I heard the bus braking, but I didn’t see anything of what happened.’

‘Okay. Can you give me some background, about Nancy and your trip over here?’

He shrugged wearily. ‘Nancy and I have known each other for many years. I was her accountant until I retired ten years ago. We both live in Boston, and since we lost our partners we’ve been travelling companions, going for weekend visits to shows in New York, or further afield, a couple of times overseas. This was our first trip to the UK together, although we’ve both been here separately in the past. We decided to have a week in London before going up north. Nancy was interested in her family history, and wanted to visit the place in Scotland where her mother’s great-grandparents came from. That’s where we were going tomorrow.’

For a moment he lost his train of thought, derailed by some memory, before he roused himself with a cough and went on.