This was confirmed by some of the eyewitnesses, especially those on the dry end of the street. Statements from witnesses downstream were, as Seawoll put it, ‘less than fucking useful’.

One woman who’d been carried away and deposited outside the RBS branch on Curzon Street said that the water had been much cleaner than she expected and that she thought she smelt meadowgrass.

‘Meadow grass?’

‘Meadowgrass,’ said Stephanopoulos. ‘One word – she was very insistent, and that’s not the strangest statement.’ Amina Asad, who’d been one of the shop workers having a fag, said she’d sort of ‘had a weird vision, you know like a really vivid daydream’ that she’d been stood waist-deep in a river washing clothes by hand. ‘By hand,’ she’d said again and laughed. ‘Like that’s going to fucking happen.’

Some reported seeing fish in the water, others a young fit-looking white boy in a loin cloth.

‘He was laughing,’ said David Hantsworth of Charnwood Drive, Walthamstow, who quite fancied getting the guy’s number, you know, should we ever catch up with him. ‘He had the coolest accent,’ according to Mr Hantsworth, who was convinced he’d been part of an elaborate bit of street theatre. ‘Like an actor doing Shakespeare.’

‘Did he say whether the guy was carrying a sword?’ I asked.

‘You know,’ said Stephanopoulos, ‘we never thought to ask.’

I added asking that question and following up the stranger eyewitness accounts to my personal action list.

Martin Chorley must have waited for his chance. At a guess, he’d been downstairs in the foyer of the same building. The sniper would have been instructed to take the shot as soon as he had a clear bead on Lady Ty – the sound of the shot would have served as a signal. Then Chorley steps out onto the street and starts his attack only to, probably, get washed away in the flood.

Thankfully the media were largely ignoring the flood, mainly because of the massive explosion that had blown out the first two floors of Tyburn’s house. British Gas, who are a bit sensitive on the subject, were desperate to rule out a gas explosion, but the only alternative the Fire Brigade would commit to involved Semtex and a truly ridiculous amount of fertiliser.

To my trained eye it looked like somebody had tried to unzip the front façade and spray it left and right. They were still pulling bits of brick and rusticated stucco out of basement areas of houses fifty metres to each side. I reckoned I’d actually seen something like it once, in an old barn in Essex, from the other side. It had been terrifyingly impressive sight back then, for all that it meant rescue from certain death.

Once Stephanopoulos had finished with her tour I found Nightingale giving the damage a cool appraisal. He shook his head and looked disapproving.