“Within a few moments of meeting someone we’ve taken on, I’ll have a good idea of whether they’ll last more than two weeks,” says Martin “Zippo” Burton, flatly, from behind a heavy wooden desk in his comfortable office trailer. “And most don’t. Most people imagine the circus to be a very carefree place, but it isn’t. In fact, it’s very regulated.”

Burton runs Zippos Circus. He used to be a clown, but it’s hard to imagine what sort. Possibly a very dry, slightly intimidating one. Zippos is playing Brighton, and more than two dozen trailers, lorries and spacious caravans are tightly corralled behind the seafront big top. He says that the circus is “quite feudal”, then smiles, “in a nice way”, with the 40-odd crew and performers “subjugating themselves willingly” to his word. In exchange, he looks after their tax problems, pensions, occasional pregnancies, the lot.

Before now, I didn’t know why anyone would run away with the circus. I like tents and I really like hotdogs, but surely it’s the most sinister place you could possibly end up? But walking around in the late afternoon warmth,with the burnt-sugar smell of candyfloss in the air, it has the sleepy feel of a continental holiday campsite, only without the noisy Dutch families.

Norman Barrett, 73, sits outside his caravan in a vest. He’s the Ringmaster, the onsite father figure who liaises between the performers and Burton, as well as dictating the tempo of the show: with 60 years’ circus experience, he can tell when performers might be having trouble and can speed things up to cover for them, or give them more time. His own performing budgies tweet from a cage. He may be the most contented man I have ever met.

The evening show starts at 7.30pm, and as the sky darkens, more performers drift from their caravans. Raul Nadler is Pepino the clown, a short, middle-aged Mexican who explains that he’s always careful not to upset any children. “Sometimes, they can be really afraid of clowns,” he shrugs sadly, a painful fact he’ll respect but never understand. I follow him backstage, where the woozy, jazzy music they pump to the audience is hypnotic, where one clown touches up his make-up and another practises catching his hat on his head. I notice that the girl who, ten minutes ago, sold me a hotdog, is now in gypsy costume and limbering up. I hear Barrett from behind the curtain, only now he doesn’t sound like a pensioner.

“Ladies and gentlemen, boys and girls,” he booms, then pauses. “It’s showtime!”

Zippos Circus is in Brighton until Sunday (www.zipposcircus.co.uk); Peckham Rye, London, from Sept 11

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