Below me, Lesley had turned back to the audience. ‘So much for the constabulary,’ she said. Behind her Seawoll sat down heavily on the stairs and slumped forward like a tired runner, the etorphine hydrochloride kicking in at last.

‘See,’ said Lesley. ‘One officer of the law kicks his last, while another lies sleeping, no doubt stupefied with drink. Thus do we good men of England put our trust in swine barely separate from the villains they purport to chase. How long, ladies and gentlemen, boys and girls, are you prepared to put up with this? Why is it that men of good quality pay their taxes while foreigners pay naught, and yet expect the liberties that are an Englishman’s hard-won prerogative?’

It was getting harder to maintain a hold, but I didn’t fancy my chances letting go. There were huge curtains either side of the stage, and I wondered if I could swing over far enough to grab one. I changed to a two-handed grip on the loop and started to shift my weight and to flex, to get momentum going.

‘Because who is more oppressed?’ exclaimed Lesley. ‘Those that seek nothing but entitlements for themselves, or those that claim for everything: social security, housing benefit, disability, and pay for nothing?’ One thing I did do in history was the reform of the Poor Laws, so I knew then that Henry Pyke must either be using stuff from Lesley’s memory or else had been reading the Daily Mail for the last two hundred years.

‘And are they grateful?’ she asked. The audience muttered in response. ‘Of course they are not,’ said Lesley. ‘For they have come to look upon such things as their right.’

It wasn’t easy keeping the rope from swinging out over the orchestra pit. I tried to correct, and ended up describing a figure of eight. I was still several metres short of the scaffolding platform, so I put my back into it, jack-knifing my legs to cross the gap.

Suddenly the crowd gave a roar and I felt a wave of frustration and anger well up around me like floodwater backing out of a storm drain. I lost concentration at a crucial moment and slammed into the curtain. I made the jump, desperately grabbing handfuls of the heavy cloth and trying to get enough between my legs to stop me sliding smack onto the stage.

Then all the lights went out. They didn’t spark, flicker, flash or do anything theatrical – they just turned themselves off. Somewhere amid the Royal Opera House’s sophisticated lighting rig, I reckoned, a couple of microprocessors were crumbling into sand. When you are hanging by your fingernails, down is nearly always the right direction, so I did my best to ignore the pain in my forearms and started working my way down the curtain. Out in the darkness I heard the audience not panicking which, given the circumstances, was much creepier than the alternative.