‘What about carriage six?’

‘Perfect CCTV, enough to show she never went in there. So we’ve bitten the bullet and downloaded all the network rail footage from platform four at Waterloo, which is where the service terminated. There are two exits, one out onto the station concourse and one down into the Northern Line, and nine cameras, so it will take a while to be sure.’

‘Okay.’

There was a big team on the case, but there were even more detectives in the incident room for the meeting than Gillard had expected. You didn’t need to be a senior officer in CID to guess that the presence of large piles of generously filled baguettes and sandwiches was strongly correlated to attendance. As well as the CCTV and information line teams, DI Claire Mulholland and DCs Michelle Tsu and Carl Hoskins were there along with DC Townsend, who seemed to be busy with his phone. The one guest was Nigel Duffy, a grey-haired inspector from the British Transport Police who looked to be in his sixties.

They were just about to start when the door opened and Chief Constable Alison Rigby strode in, power dressed in a houndstooth jacket, black slacks and court shoes. Her arrival chilled the atmosphere faster than the arrival of the Salvation Army at a lap dance joint. Rigby took a seat at the back, as if pretending that would in some way make her more incognito.

Gillard called the meeting to order, and after a few introductory remarks summarised what they knew so far. ‘Beatrice Ulbricht, twenty-five, an accomplished violinist studying at the Royal College of Music for an MSc in musical performance, has been missing since Tuesday afternoon when she boarded the 15.48 Waterloo-bound train at Clandon just east of Guildford. Had she remained aboard, she would have arrived in London about an hour later. And we know for a fact that her phone did arrive in London. It was finally found at the Brentford waste transfer station, and the cell site analysis corresponds with the movement of the contractor’s waste consignment from Waterloo. We are assuming it had been deposited in a waste bin somewhere on that train.’

Gillard dimmed the lights, set up his laptop projector and activated the video screen. ‘This is Ms Ulbricht getting on coach eight at Clandon. As you can see she is hard to miss. Not only the mauve fedora, but that distinctive rainbow scarf, the navy blue overcoat and the violin. We’ve already had a half-dozen calls to the information line from people who saw her during the early part of the journey, and we should get more after this afternoon’s press conference. As is typical with eyewitnesses, they notice her getting on and taking a seat, and when she moves to a new carriage. We’ve nothing firm on where she got off.’

The CCTV footage showed her taking a seat right under the camera at the rear of the coach. Gillard paused the video and clicked on another, edited from the coach footage. This showed her getting up and walking the length of the carriage, and through to the next coach. ‘This is carriage seven, where the CCTV doesn’t work. We must assume she continued her journey in this coach because there is no sign of her on carriage six, where both cameras were working.’