If they did, wouldn’t they be much more powerful than those left behind by people? Or was that a typical first order assumption? Probably, I thought. And yet, if we stayed with that idea then surely the world would be full of these powerful ghosts of former gods. Now, I hadn’t come across anything like that in my literature and while my predecessors in the craft were often thicker than a bag full of custard I think even they would have noticed something like that.

Perhaps, I thought, the dead god gets folded into the existence of the new god, the way a dormant genetic variation can exist within an organism’s DNA – hanging about like an actor’s understudy until the right environmental conditions give it expression and – hey presto – suddenly a bacteria is heat resistant, our Chloe gets her big break on Broadway and a sniper for hire gets an unexpected half a metre of cold steel through the chest.

Perhaps that explained why the rivers of London had burst forth with new goddesses so quickly after Mama Thames took up her throne. Perhaps there was more than historical continuity between the dead sons of old Father Thames and the daughters that had taken their place.

And a certain river on the Welsh Borders where me and Beverley had been ‘catalysts’ in the creation of a new spirit, a new genius loci, a new god.

Shit, I thought, I’ve just invented epideism.

‘Peter,’ said Stephanopoulos. ‘You still with us?’

‘Oh, god,’ I said. ‘I think I preferred being a frog,’ And then, before Stephanopoulos had a chance to clip me round the ear for being obscure, I told her I’d have to do some digging on the subject.

‘But we still need to see if they find any metal fragments in the wound track,’ I said and reminded myself to ask Dr Vaughan to do the most sensitive test she could, because if she couldn’t find any then it was possible that the sniper had been stabbed with a sword that didn’t physically exist.

What had definitely existed was the water that had erupted out of the street in front of Lady Ty’s house. A burst water main, according to Thames Water, who said they’d get back to us as to why it had chosen to burst at just the moment Mr Sniper was getting an invisible sword stuck through his chest.

Tyburn’s street had a noticeable slope north to south and you could see from the water damage where the flood had risen outside her front door and rolled down hill, across Curzon Street, down the passage under Curzonfield House before emptying out into Shepherd Market. Much to the surprise of the shop workers who’d been sitting on the benches having a quiet fag at the time.

‘It was two feet deep,’ said Stephanopoulos.