Tyburn lived a kilometre east of One Hyde Park, just off the Shepherd’s Market, in a five storey Georgian terrace whose elegant proportions would have caused the most hardened Canadian property developer’s soul to weep to see such beauty – just prior to having the place gutted and filled with the latest in personality-free interior design. I couldn’t see Tyburn doing that – she wanted the connection with the past, with the old institutions and traditions of the city. She saw it as her birthright.

I rang the doorbell and as we waited me and Guleed intoned the Londoner’s lament.

‘Look at this place,’ said Guleed.

‘I know.’

‘How much do you reckon?’

‘Eight million,’ I said. ‘Last time I looked.’

‘Alright for some,’ said Guleed, to which my ritual response would have been ‘isn’t it just?’ But right then the front door opened and Lady Ty stood there looking at us if we’d turned up with some colourful pamphlets and an evangelical zeal to get her to change her energy supplier.

I let Guleed do all the talking – I’m good that way with my colleagues.

When Lady Ty led us into the kitchen, Olivia wrinkled her nose and shot an inquiring look at her mother, who cut her off with a glare.

Olivia McAllister-Thames was pale, much lighter than me, with brown hair that fell into the sort of natural ringlets that my mum would have sacrificed her first born to possess. She’d retained her mother’s eyes though, a deep brown colour and pinked up at the corners like a cat’s. She wore an oversized amber rugby jersey that fell almost to her knees, jeans and purple flip-flops. Sitting next to Olivia was a white middle-aged man who Lady Ty introduced as her solicitor. He got up politely as we entered and shook our hands – Olivia did not. We all sat down at the kitchen table.

Outside London, modern policing leans towards table-free interviews on the basis that it’s easier to read someone’s body language, and record it on CCTV, if there isn’t a cigarette scarred stretch of laminated chip-board in the way. I wondered if Lady Ty knew that, which was why we weren’t doing this in the living room – or if she just didn’t want me rifling through her Blu-ray collection.

Guleed passed me the statement form, so I had to hunt around in my pockets for a decent pen. Most statements are taken by hand, and it pays to picky about your writing implements and cultivate an easy flowing style – I use a Mitsubishi uni-ball, in case you were wondering.