Longhurst took a seat. He moved very carefully, perhaps because he was so tall, sitting with a straight back and reaching for a bottle of sparkling water with elegant fingers. He was in his mid-thirties, with the easy confidence that comes from either inherited wealth or early success, a completely different man to the one I had met in Euston. Could it be that he changed his persona depending on the client he found himself with, that the richer and more established they were, the more suave and self-confident he became?

‘So, how can I help you gentlemen?’ he asked eventually.

I had no answer. It embarrassed me that I still had no idea why we were here.

‘Well, obviously we want to talk to you about Harriet Throsby,’ Hawthorne said.

‘I’m not sure I have anything to tell you.’ Longhurst chose his words carefully. ‘Certainly not in relation to her murder. My client, Mr Yurdakul, told me about it yesterday and you can imagine my reaction.’

‘How long has Mr Yurdakul been a client?’

‘I first met him about eight years ago when he came in to develop a software system for this company. He did a very good job. When he decided to set up as a theatrical producer, he asked me if I would look after his accounts, and although I will admit he didn’t quite fit the company profile – or the profile my partner and I were hoping to create – I agreed. I’m very sorry it hasn’t worked out for him, but I’m sure he’ll bounce back. He’s nothing if not resourceful.’

‘Did you know that Harriet Throsby would be at the theatre?’

‘It had occurred to me that she might be there. I don’t know why you’re asking me that question, Mr Hawthorne. Do you think I’m in some way connected to her death?’

‘Well, you were one of the last people to speak to her.’ Before Longhurst could deny it, Hawthorne went on. ‘I understand that the two of you met at Topkapi, the Turkish restaurant, after the play finished.’

Longhurst hesitated. ‘I spoke a few words to her in a crowded room,’ he admitted. ‘We said nothing of any interest whatsoever.’

‘Are you saying you’d never met her before?’

I saw the flicker of annoyance in the accountant’s eyes as he realised that he wasn’t going to be able to hide the truth. ‘No. I haven’t suggested anything of the sort. As a matter of fact, we did cross paths once, but that was a very long time ago. About twenty years, in fact, although I’d prefer not to discuss it.’

‘I’m sure you’d prefer not to, Mr Longhurst. Unfortunately, when someone is murdered – and in a particularly brutal way – there are questions that have to be answered.’

‘I didn’t kill her.’

‘But you had a good reason.’

‘Did I?’

‘She wrote a book about you.’

And there it was. As soon as I heard Hawthorne’s words, I realised what I’d missed. There had been three books on the table in Harriet Throsby’s office in Little Venice, all of them written by her. One of them was called Bad Boys: Life and Death in an English Village. Arthur Throsby had described it to us. ‘It was about Trevor and Annabel Longhurst. You may remember them?’ Their son had been involved in the death of a teacher. Longhurst wasn’t that common a name and Hawthorne must have made the connection immediately.