Simon Pegg caused much cosplay action at the London bash.

It's Sunday morning at an extremely characterful Excel Centre, and Rogue Pun has pitched up early for an entertaining panel about parallel universes, featuring the dapper film critic Kim Newman (although alas no David Quantick yet, the On The Hour/Day Today/Thick Of It writer having been unexpectedly trapped in the parallel universe of the UK rail system).

This being an open-sided venue, though, it's easy to get distracted by the sight of stormtroopers, dark Jedi and imperial officers lined up against a Death Star-style backdrop right next to the Creator Stage. Then Shaun and Ed from Shaun Of The Dead start posing, and we rudely pop off mid-panel to say hello.

It's not really Shaun and Ed of course, given that they're mythical characters - in fact the duo playing them here are from a division of the UK Garrison, a high-end cosplay team who raise money for charity by pitching up at events like this, chiefly with a photo-friendly troupe of Star Wars icons. Hence them hanging out near the Death Star area, as Shaun and Ed definitely would. "It's the first time Simon Pegg's been at MCM London," says 'Shaun,' "so we thought we'd do the costumes as a tribute."

Simon Pegg is indeed here, and MCM Comic-Con will go Cornetto-crazy over the weekend. Pegg is pretty much the perfect comic-con guest, when you think about it. His breakout project, Spaced, was a full-on paeon to all things geeky, and he's gone on to appear in some of the biggest sci-fi franchises: Star Wars, Doctor Who, Ready Player One, the new Dark Crystal on Netflix (alongside the likes of Eddie Izzard, Mark Hamill and Toby Jones), and particularly Star Trek, the movie reboot that he went on to co-write. His alien movie Paul was a bit of a love letter to comic-cons, too.

Pegg is in town Saturday and Sunday, but Rogue Pun's comic-con kicks off on Friday, where the Cornetto action is already in full swing. The first person we see after wandering in, in fact, is a policeman holding a swan - it takes a second to realise that it's not a local bobby getting involved, but someone dressed as Danny Butterman from Hot Fuzz, a scene that's since become semi-newsworthy again. That's one of the great quirks of comic-con: every time you see a steward you wonder which film they're from, and vice versa.

We'll also spot people dressed as Rafe Spall and Paddy Considine's Hot Fuzz coppers, the two Andy's, numerous zombies, while the artists and t-shirt stalls have got their Pegg-related merch to the fore: Sandford Police t-shirts, pub beermats from the Winchester, and lots of fine posters. The illustrator Sam Gilbey is particularly on-point: his Cornetto trilogy posters are just perfect for those who've signed up to get stuff signed, over the weekend. They've been given the thumbs-up by Pegg and Edgar Wright, too.

Elsewhere, Friday's big draw is Jason 'Aquaman' Momoa, here showcasing his Apple TV show, See, although his co-star on that panel, Alfre Woodard, has some impressive sci-fi credentials too: she's one of the few actors to play two roles in the Marvel Universe. Yes, Chris Evans (not that one) was both the Human Torch and Captain America, but for two separate studios (Marvel's cinematic family is complicated), while Mahershala Ali played charismatic villain Cottonmouth and the forthcoming Blade.

Woodard, though, has already played two seriously significant characters: the scheming politician Mariah Dillard across two series of Luke Cage, and also Miriam, the enraged mother who kicks off the whole Cap/Iron Man feud in Captain America: Civil War. She was also in Star Trek: First Contact and - most impressively as far as we're concerned - played Bill Murray's Cratchit-esque PA, Grace Cooley, in Scrooged. Now that's a comic-con friendly CV.

We're elsewhere on Saturday so miss Mark Gatiss and Steven Moffat talking about the forthcoming Dracula, sadly, but are back bright and early on Sunday for full-blown Peggcitement. There are LOTS of Shauns about, it being a fairly simple costume to attempt - blood-splattered white shirt, work badge, cricket bat - while every other type of cosplay is also on display: various iterations of Doctor Who, Deadpool riding a unicorn, and our favourite - causing a stir in the queue for Pegg's talk - two ladies dressed as Hell's Grannies, from Monty Python's Flying Circus.

Turns out they've been taking their kids to comic-con - or the other way around - for a while, and this year they decided to get amongst it. Which conjures visions of them encouraging a whole posse. One day there'll be a UK garrison of Hell's Grannies, striding up and down the aisles whacking Darth Vader, Thanos and The Joker with their handbags.

Our comic-con will end with a fascinating panel about creative inspiration, which David Quantick does thankfully escape the trains in time for. But the big event is Pegg's show, and there's a mighty queue outside the Main Stage, which is also the best queue you've ever seen of course: lots of Shauns and superheroes and at least one big floppy dinosaur who you really don't want to be stuck sitting behind.

Pegg marches on in full rock star mode - then brings on our two cosplay pals from earlier, and gives the UK garrison's charity stuff a nice plug. The panel is hosted by the excellent Claire Lim, who teases some fascinating stuff from him, about projects past and upcoming.

His production company with Nick Frost, Stolen Picture, will soon be bringing us the series Truth Seekers, which sounds fun, with Frost heading a team of paranormal investigators and Pegg playing his boss (Pegg was a bit busy to take a full-on role).

He also takes us behind the scenes of Cornetto stuff and the two Stars, Wars and Trek: if you'd told the teenage Pegg that one day two characters he plays would run the Starship Enterprise (Scotty) and own the Millennium Falcon (Unkar Plutt), he'd think you were a nutter.

But best of all is his round-up of what happened to the characters from Spaced. Tim and Daisy got married then split, but Mike found happiness with another dude; we forget what happened to Twitch, but Brian died, then his paintings became posthumously famous, then it turned out he'd faked his own death. And Marsha still lives upstairs.

Somewhere in the Excel there's probably someone doing a Marsha cosplay. Glass of red and a ciggy, anyone?