God, it was hard not to move. But I knew that Nightingale could throw sounds about the place. And if Chorley had really been behind me I doubted he would have been so chatty.

‘What I don’t understand, Peter,’ said Martin Chorley – but now his voice seemed to be coming from a spot three or four metres to my right – ‘is your loyalty to these institutions. The police, the Folly – you swore an oath to the crown for god’s sake – institutions with hardly the best track record with regards to you people.’

Because the alternative is you, I wanted to shout back. But the second lesson on how not to be seen is: Don’t answer back.

He knows he’s short of time, so he’s trying to provoke me, I thought. Next, escalation – threaten somebody else.

‘I’ve got your Muslim partner,’ he said. And this time I spotted the voice wow-wowing back and forth through the trees. I thought I might even be able to sense, just a little, the formae he was using to do it. ‘You have a reputation for gallantry – are you perpared to do the gallant thing now?’

Now, he might have Guleed, although I doubted it. But even if he did, I knew he wasn’t going to just swap me for her. He was trying to provoke a response so he could zero in on me.

And if he did have Guleed?

I thought it better to establish the facts before I started worrying about that.

I decided to give him a response.

Lux is really the most ridiculously versatile of the formae and it has been the subject of experimentation by literally thousands of practitioners since the Folly was a bunch of likeminded weirdos and charlatans meeting in a London coffee house. As a result, a young person with an inquiring mind can find the most extraordinary things written in the margins of his textbooks. Now, I have the advantage over my nineteenth century peers of knowing what infrared is and how it relates to imparting heat energy to a small cloud of gas so that it expands with a humorous farting sound – oh, how they must have laughed. Thus I can make my farting sound louder and funnier – to the point where it can shake the branches on a small bush.

Ipsa scientia potestas est.

I call them noisemakers because I haven’t thought of a decent Latin tag yet.

So I flipped one as far to my right as I could, where it made a sound like a deflating bellows and made a bush shake.

Let’s see what you make of that, I thought.