'We'll stay in touch,' he said, shamed by the lie.

'It's probably best that I should wait to hear from you,' said Sebastian civilly. 'Take care, old chap. Don't leave it too long, eh?'

The cab pulled away and disappeared into the afternoon traffic. Vince knew that this was an official end to their meetings, just as Sebastian knew that there would be an unofficial continuation. He should have been relieved, but one thought kept running through his mind. What if I've made a mistake? Suppose he's reformed since those articles were written, does it really matter what his politics are? What right do I have to judge him on the events of the past?

On the Tube back to Tufnell Park he found it hard to shake the terrible sense of foreboding that had descended upon him. Suppose there was some kind of comeback from all of this?

Some things in life were dangerous; that was knowledge quickly learned. A burning cigarette-end flicked from a car. A bad neighbourhood late at night. The sound of breaking glass. Voices raised in drunken anger. These were reasons to be fearful. When Vince was a child, his father used to show him how his open razor would slice through a sheet of paper just by resting the blade on the top of the page. Its casual power appalled the sensitive young boy; it was intended to.

He had been an easily frightened child. His world was darkened with dangers. His father's timidity was as inoperable as cancer, and it had turned him into a bully. His endless warnings destroyed the little confidence his son possessed. Harm was found hiding in the most mundane events; the turn of the tide could transform a beach stroll into a race against the incoming sea. A picnic in the woods could conjure images of the family lost and starving among lightning-blasted trees. In his father's world, the simple act of replacing a three-pin plug became a feat so fraught with electrical hazard that only a fool would attempt it. The destruction of his confidence, Vince came to realise, was the most damaging childhood loss of all.

When his father died, Vince cried because they had not been able to resolve their differences. He had wanted to show his father that all those years of cautionary advice had been wasted, that far from being scared to live he was now ready for anything the world could throw at him. One week after the funeral, Vince left his mother's house to seek adventure in the city. Now that he had finally found it, he began to realise that there were bigger things to fear.

'YOU WON'T find much written down about them. They're not the sort of organisation that likes to leave hard evidence lying around.'

Vince finally managed to collar Dr Harold Masters on the steps of the British Museum, where he had just delivered a lecture on the celebrations of the Inca calendar and early Mayan beliefs, and was now hurrying through the early evening drizzle, anxious to get home. Vince was late and lucky to have recognised him at all, considering he only had Esther's description ('absurdly tall, unsuitable tortoiseshell glasses') to go on.

'You'll have to walk with me, I'm afraid,' said Masters, striding ahead. 'My wife will kill me if I'm not on time. We've some Egyptian ceramics people for dinner and they're unfamiliar with the concept of fashionable lateness. Come under shelter. Pity about this weather. It was so nice yesterday.' He was carrying a gigantic green and white striped golfing umbrella.

'In the twenties they were known as the Young Prometheans. Information on them is all rather hazy. No idea why they linked themselves to Prometheus, except of course Mary Shelley's Frankenstein is subtitled The Modern Prometheus, isn't it? Enlightened man, and all that. The heyday of such societies was in the Victorian era, of course. They always picked classic-sounding names with quasi-mystical connections. The League is almost certainly Edwardian in origin, although it seems to have a group of founders rather than one single leader. It began as little more than a splinter group of an Oxford debating society, that much is sure, but its character changed during the Second World War.'

'Why was that?' he asked, hopping ahead to keep abreast of the doctor.

'Oh, for the simple reason that they supported Mosley during the conflict. Around this time they gained the support of the British Union of Fascists, oddly enough through their mutual admiration for Edward the Eighth – the BUF were royalists to a man – and of course the Mitfords began throwing money at them. But the alliance with the Black-shirts marked a move to the far right from which they never recovered. Of course, all sorts of odd things happened in the war. That forecourt, for example,' he indicated the museum at his back, 'was full of onions, runner beans and cabbages, a victory garden dug up by the wife of the Keeper of Coins and Medals.'

'There's something I don't understand, doctor.' Vince paused with him as they reached the kerb. 'What exactly does the League do?'

'That's an interesting question.' Masters rolled his eyes knowingly. He looked slightly mad. 'Their actions certainly seem to be more negative than positive, rather like a radical mini-version of the House of Lords. Basically, they prevent things happening that they don't agree with. From the wealthy backgrounds of their associates I imagine they operate some kind of privilege system that allows their members to get on at the expense of others. You know, do subtle, appalling misdeeds to the underclass and always manage to hush them up, place favoured sons into the jobs their fathers had before them, that sort of thing.

'A few years ago I ran afoul of them when I wrote a monograph on the later history of the city guilds. In the course of my research I upset a few younger members of the Oxbridge set by suggesting that the City of London corruption cases of the eighties could be traced to the exclusion practices of the old boy network, and I went as far as to name a few of the culprits. I had no idea they were Masons. Next thing I know, this chap Wells calls me up – on my unlisted number, no less – and actually has the audacity to threaten me, in the most affable manner conceivable, but still a threat. Tells me my research is based on false assumptions, perhaps I'd care to rethink my proposals, or he'll be happy to have some of his colleagues come around and help me with the revisions.'

'What did you do?'

'What could I do? I'm an academic, not a gladiator. I amended the document to exclude them. Funny thing, though, I was introduced to Wells at a party a few months later and he was charm incarnate. I didn't much care for him, swanning about as if he owned the place. The city, I mean. Struck me as your classic bright boy gone to the bad. A head full of silly ideas and no practical abilities. Wealthy people always assume they have the right to be eccentric.' He halted at the corner of New Oxford Street and peered beyond the edge of the umbrella. 'If you're thinking of getting mixed up with these people, I'd bear in mind that they have some pretty powerful friends. And I should think they can be dangerous. I don't know that they've actually ever killed anyone, although there was some speculation about a journalist who died slipping on some steps, but over the years they've exerted a lot of pressure on specific targets. Still, you can't be too careful. There's nothing more harmful than an opinionated intellectual with too much money.'

'Thanks for the advice. I'll bear it in mind. Just a couple more questions.'

The doctor was busy searching the rainswept street for a cab. 'Fire away,' he said, distracted by his need to find transport quickly.

'How many members of this society are we talking about?'