There was only one doorbell and the small front garden was given over to gravel, the dustbins and a couple of empty, bright red plant pots. I was thinking that either Dr Framline owned the whole place or he was sharing with friends. I pressed the bell and a cheerful voice said it was on its way. The voice belonged to a plump, round-faced woman of the sort that develops a good personality because the alternative is suicide.

I showed her my warrant card. ‘Good afternoon. My name’s Peter Grant, I’m from the police and this is my colleague Beverley Brook, who’s a river in south London.’ You can get away with stuff like that with civilians because their brains lock in place on the word ‘police’.

Actually I think I may have overdone it because the woman frowned at Beverley and asked, ‘Did you just say she was a river?’ Which is why you should never show off when on duty.

‘It’s an office joke,’ I said.

‘She seems a bit young to be police,’ said the woman.

‘She’s not,’ I said. ‘She’s on work experience.’

‘Can I see your identification again?’ asked the woman.

I sighed and handed it over. Beverley sniggered.

‘I can give you the number of my superior if you like,’ I said. This normally does the trick, since members of the public are generally lazier than they are suspicious.

‘Are you here about what happened at the hospital?’ asked the woman.

‘Yes,’ I said, relieved. ‘That’s exactly why we’re here.’

‘Only Eric’s gone into town,’ she said. ‘You just missed him; he went fifteen minutes ago.’

Of course he has, I thought, no doubt to some spot less then five hundred metres from where Beverley and I started out. ‘Do you know where he was going?’

‘Why do you want to know?’

‘We think we have a line on the man who attacked him,’ I said. ‘We just need him to confirm a few details. If we do this quickly we may be able to make an arrest tonight.’

That perked her up, and got me not just the name of the gastropub Dr Framline was heading for but also his mobile number. Beverley had to trot to keep up with me as we headed back to the car.

‘What’s the rush?’ she asked as we climbed in.

‘I know the pub,’ I said. ‘It’s on the corner of Neal Street and Shelton Street.’ I pulled out without waiting for Beverley to buckle up. ‘Right across from there is the pedestrian space outside Urban Outfitters.’

‘Urban Outfitters, eh,’ said Beverley. ‘That explains the Dr Denim shirt.’

‘My mum bought me that,’ I said.

‘And you think that’s less embarrassing?’