When I’m in my 80s, I won’t be as cool as Glyn. He’s sitting opposite me on the Brighton seafront, wearing blue-tinted spectacles, a well-worn docker cap and a single dangly earring. He’s an activist, yes, how did you guess? But his cause is unusual. He’s spent a lifetime in the service of a violent man, amplifying his message to an impressionable audience of children. For Glyn is a representative of Mr Punch.

Punch (husband of Judy, ne’er-do-well, puppet) has been causing mischief in the UK since at least 1662, when Samuel Pepys recorded seeing an ‘Italian puppet play’ in Covent Garden, featuring the marionette Pulcinella. This character would gradually transform into the erratic hunchbacked, red-nosed glove puppet Punch, and accumulate a revolving cast of supporting characters: his wife Judy, their baby, a policeman, a crocodile, a clown and the devil, to name a few. There will usually be sausages. There will always be characters hitting each other with a big stick.

As silly as it all is, Punch performers (‘professors’, as they are known in the biz) are caretakers of a tradition stretching across three centuries of continuous performance, tracing a direct line back to a Britain of the very distant past. Every few years, the breakfast show sofas and Mumsnet threads are animated with conversations about cancelling Punch and his old-fashioned wife-bashing, baby-throwing ways, deeming him an inappropriate model for children. Long beleaguered by these protestations, the profs have a unique place in a cultural landscape characterised by debates around free speech and censorship. And that’s why I’ve come to the chief professor himself.

Since seeing his first show in the 1940s, a stone’s throw from where we are now on Brighton beach, Glyn’s life has revolved around the booth. Gradually, he has become the foremost authority on the subject, and last year he assumed charge of the Punch and Judy Fellowship, a position of authority that clearly plays on his mind: ‘I can only be president as long as I can do it within the spirit of which Mr Punch would approve’.

So he’s careful to resist becoming a gatekeeper. As it stands, the only restriction in becoming an authorised PJF professor is use of the swazzle, a reed suspended in the throat to create Punch’s squeaky voice. ‘It shifts Mr Punch into being a kind of musical instrument. It places a complete barrier across the show ever developing into a simple hand puppet play. The whole thing lifts off and becomes a Punch and Judy show.’ I volunteer that the swazzle, in combination with other classic elements of the show, creates a sacred space where the violence and transgression can exist, separated from the real world. Assenting, Glyn requests that I note the term ‘sacred space’ came from me, not him. ‘My colleagues who might read this would take umbrage at a term like that’.

Whatever we call it, there is an understanding between performer and audience that the world of the show is not our own. ‘There are different rules of life, death, violence.’ A world of slapstick (a term taken from Punch’s weapon of choice), whose rules are implicitly understood by children, but frequently misinterpreted by adults. The violence is part of the very fabric of the show. ‘We despise the people who go, “Oh, I do a politically correct Punch and they don't hit each other.”’ Indeed, many a well-meaning academic has attempted a feminist or post-colonial or Freudian Punch. It doesn’t tend to work.

But over the years, some concessions have had to be made to modern tastes. Sacred space or not, the show has had to move with the times. For much of the twentieth century, Punch would be accompanied by his canine companion Toby, a real dog. The decision to replace the performing animal with another puppet was ‘one of the first signs Punch was under scrutiny’.

One classic routine involves a botched attempt to hang Punch for his crimes, in which the hangman is tricked into placing his own neck in the noose. With a deft movement, the prof’s life-giving hand exits the hangman, leaving the inanimate puppet swinging from the gallows. The decision to move away from this moment is less a case of shock factor than relevance, Glyn explains: ‘When I was about eight, they hanged Derek Bentley, and all the kids were talking about it. At school you could get in trouble for stuff, and as an adult hanging was the ultimate telling off.’ With today’s eight-year-olds somewhat less exposed to capital punishment, there is a general consensus to leave the sequence out. Those who insist on a hanging won’t find support from the Fellowship: ‘On your own head be it’.