Gillard left a short message asking Deepak to ring Surrey Police, adding: ‘Mr Tripathi, If you’re thinking of flying out of the country, we flagged up your passport for an immediate arrest by border control.’ After he hung up he looked at his own watch. Victoria had bought her boyfriend fifteen minutes of valuable time, and at the speed he drove, he could have made twenty miles or more on them. Gillard was relieved to see the arrival of a patrol car, so he could hand over this nuisance of a woman to them. He had to admit she had played her hand pretty shrewdly. They would probably not even be able to get her for wasting police time.

Colin Hodges and Rob Townsend were furiously working the phones, trying to co-ordinate more mobile units with Gillard’s location, and get a more timely fix for Deepak Tripathi’s mobile phone. The latest data Townsend had was fifteen minutes old, and quite sketchy, but seemed to reinforce the idea that the company director had been travelling at speed east along the A3 towards London. The two detectives stared at Hodges’ computer, which showed the Google map they had just been emailed and which had cell tower locations superimposed.

Hodges’ desk phone rang, and he snatched it up, expecting a further location update. Instead it was the female desk sergeant at Epsom, saying she had a man called Zayan Lal who had walked in. ‘It’s in response to a request from you for a DNA sample, something to do with the Roy case. He has also brought some flight paperwork and his passport.’

‘That’s great,’ Hodges replied. ‘Can you swab him, and get it couriered off to the lab as urgent?’

‘Okay. What you want to do with the flight paperwork?’

‘Just check through it and see that it matches the Border Force e-gate record.’ He gave her the case number, and asked her to photocopy the documents Lal had brought in. He thanked her and ended the call.

‘Who was that?’ Townsend asked.

‘One of Harry Roy’s mates,’ Hodges replied. ‘Now, have we got anything more on Tripathi?’

‘No. They just emailed me to say the phone’s been switched off.’

‘Last position?’

‘Heading west on the A30, just before the M25 junction.’

The two officers looked at each other.

‘He’s going to do a runner, isn’t he?’ Hodges asked.

Townsend nodded.

‘Right, I’ll do Heathrow, Luton and Stansted,’ Hodges said. ‘You do Gatwick and London City Airport.’

‘I’m going to start by requesting the metadata on his phone,’ Townsend said. ‘We’ve got the warrant, but usually takes two to three hours to get it through the service provider lawyers. I want to find out if he has any e-tickets on his phone.’

‘Good idea.’

‘Shame we don’t have his actual phone, we could have put it through the data kiosk and have the dates in half an hour,’ Townsend said.

‘Such is life,’ Hodges said. They both picked up the phones and went to work.