Harry Potter Live

4.00pm: It all ends. Finally. After what feels like just 500 short years, the Harry Potter film franchise tonight comes to a finish. Or at least starts the beginning of that finish - the world premiere in London being only the first of many before the actual opening date (next week). And then there's the DVD and Blu-ray etc, so actually it'll be 2013-ish before we can stop hearing about the boy wizard.

But anyway, for the next three hours join us as we watch a live video stream of the festivities in Trafalgar Square, where the cast and crew will meet fans who've been camping for days, before proceeding via specially decorated alleyways to Leicester Square, where the film will simultaneously premiere in three cinemas.
We'll have on-the-ground updates from Sam Jones, Xan Brooks and Shehani Fernando.
Warning: Muggles are operating in this area.

4.02pm: Are you at the premiere too? Please email or tweet over any thoughts (@guardianfilm) and observations, or, javascript willing, stick em in the comments.

4.03pm: It's all kicked off: Alex Zane and Edith Bowman are the hosts, and having to bellow a bit over the screams.

Zane is chatting to fans who've been there 55 hours. "It's certainly exciting," they say. You'd hope so.

4.05pm: Coming up soon we'll have Peter Bradshaw's review of the final film in the series and, without giving too much away: it's a surprising one.

There's so much red carpet in the square it's all looking slightly DFS.

4.08pm: An update from our own Xan Brooks, live in Trafalgar Square, and a bit appalled:

Thousands of people screaming at nothing (stars still absent). So far: less JK Rowling, more Don DeLillo.

4.12pm: Not really a lot going on on that livestream: lots of excited chat about the crowds and the sun and the enormous amounts of cash that the franchise has made.

4.13pm: Every one of the Harry Potter stars will be interviewed, we're told. And if there's anything you don't know yet about Harry Potter, we'll tell you. Ominous stuff.

4.15pm: While the cast and crew rave on v/t about the comedy genius of Rupert Grint, we bring you news that family history website findmypast.com have leapt onto the Harry Potter band wag- errr broom and dug into the history books to find a real-life wizard. The 1911 census of England and Wales includes a Mr. John Watkins Holden of Worcester, who was a self-proclaimed 'Wizard of Ye Wicked World' working in the 'magic' industry. John was registered on the census as a wizard for over 40 years. It's a cut above listing your race as Klingon, isn't it?

4.18pm: More interviews with fans, most of em most excited to meet JK Rowling, interestingly. "It's like she's given us this gift … it's just a present to us."

4.21pm: V/t on Emma Watson now. "She's incredibly ambitious," says someone.

4.21pm: Bit more from Xan:

Elderly businessman leans out of passing taxi to shout: 'Harry Potter lives!' Cue deafening cheers.

4.22pm: Rupert Grint has arrived! You can read Tom Lamont's brill interview with him from last week's Observer if you like. Alex Zane very excited to know how the "traumatic love triangle" of Part One will end. But even more excited by the "incredible carpet".

4.25pm: Is Grint's suit black leopardskin?

4.27pm: This just in. James and Oliver Phelps, the actors who play twins Fred and George Weasley will be dry this evening. The pair will be decked out in water-resistant three-piece suits designed by David Brooke of Mathieson & Brooke tailors.

Best not mention that to fans who've been camping out in Trafalger Square. They've braved up to 72 hours of drizzle to see these two saunter up the red carpet in their practical attire. Bit galling really.

4.27pm: Rupert Grint interviewed by Alex Zane - not going to go down in the annals. Edith Bowman faring better with some Swedish zealots.

4.33pm: Neville Longbottom has just arrived on the red carpet. Yup.

4.37pm: Jason Isaacs is here and "groomed differently" to his character, Lucius Malfoy. He is wearing a black shirt, a black suit and black shoes. His hair? That too is black. That's where actor and character part ways. This kind of insight takes an expert eye, you know?

4.42pm: Jason Isaacs is talking to Edith Bowman about playing Lucius Malfoy. The last word he said during filming was "Help!" and the first words he said, way back in 2001's Philosopher's Stone was "Now, now Draco. Play nicely." Isaacs then recounts a charming anecdote about smacking a child on the hand with a wand and making him cry. He got paid to do that. It's a crazy, crazy world.

4.51pm: Tom Felton (who plays Draco Malfoy) is putting his scribble to the bits of paper, body and dignity that the clamouring crowd are offering him. If that sounds snobbish you should listen to the live commentary. They've called the crowd "smelly" countless times already.

Meanwhile Evanna Lynch has emerged from a black car and has joined Tom in the signing. She plays, Luna Lovegood, the Bond girl that never was.

4.59pm: Michael Gambon is here.

Michael Gambon has very large hands. Yesterday all of the cast were asked to sink their digits into a plaster cast. Leavesden studios (where the Potter movies were filmed) will be displaying all of the moulds to celebrate the franchise. All except Gambon's. Who's hands were too big to fit the mould. Now, THAT's real news for you.

5.04pm: Michael Gambon 100% stealing the show: "Oooh look, I'm on the telly."

5.05pm: So, hello to the both of you still with us, and remotely interested in what Molly Weasley thinks in real life, and not following any other live blogs that might or might not be happening at the moment.

5.07pm: Evanna Lynch (Luna Lovegood) chews the fat with Edith Bowman, as strange towering braziers burn away in the background, like at a steak house or a picket line. Lynch has forgotten the question.

5.13pm: Some colour from Sam Jones at the scene:

Enterprising fellow selling plastic ponchos for THREE QUID ... And the sun
is coming out.

5.14pm: Soon-to-be-Dame Julie Walters speaks of the agony of Wand Arm, the RSI of Hogwarts.

5.16pm: Ominous clouds gathering above St Martin's.

5.17pm: Breaking news: Alex Zane reveals "we are absolutely trending round the world now." One of the twins reveals they've been asked to sign a banana.

5.21pm: Very interested to read Robbie Collin's review in this Sunday's News of the World (was being written about an hour ago).

5.22pm: Shehani Fernando has sent us in some video from the scene.

5.24pm: Here's Peter Bradshaw's review of Deathly Hallows: Part 2.

Rupert Grint is grinning through his second interview, this time with Edith Bowman. He says: "The fans are the reason for all of this. They are amazing". Our own Xan Brooks agrees, but worries for them too:

Words I never thought I'd say: Potter fans are delightful. Warm, smart, likeable kids. Some of the cops, by contrast, seem to have confused the premiere for a picket line. Lots of bullish "crowd-control".

5.28pm: Domhnall Gleeson (who plays Bill Weasley) has been very, very good in lots of things: Mark Romanek's Never Let Me Go, The Coen's True Grit, Tom Hall's Sensation. Now he's very, very good in A Slightly Awkward Interview On The Red Carpet. He says he "was a Weasley, before he was a Weasley". Because of the red hair, of course.

5.35pm: Xan Brooks has been polling fans at the premiere and has come back with the definitive answer to the question that at least a Trafalgar square-ful of people are desperate to have resolved: Which of the eight is the best Harry Potter movie? Xan says:

Every fan I ask names the same one, which surely makes it official. Film No. 3 - The Prisoner of Azkaban - is the best (though naturally none of them have seen the last one yet).

5.43pm: We've got a whole load of snaps of actors pretty and carpet red up here.

Meanwhile another of the many, many Weasleys is up on stage: Bonnie Wright, who plays Ginny, is being grilled by Edith Bowman. Across the way, director David Yates is facing Alex Zane. His favourite part of shooting was the final confrontation between Harry and Voldemort and he managed to snaffle [something] from the set before the production wrapped. I missed what is was. My guess would be "good times".

5.54pm: "We've got loads more Harry Potter facts coming up that you can take into school tomorrow and impress your friends with," says Alex Zane, giving adults watching (and live-blogging) something of a reality check.

Proper grown-up Robbie Coltrane is over with Edith. He calls Deathly Hallows: Part 2 "terrifying and beautiful".

6.01pm: The cars with the stars keep rolling up to the carpet.

Emma Watson and Ralph Fiennes are running the gauntlet now. Watson has reached the stage and waves both hands in a windmill motion across the crowd. The Celebriatus spell is cast and the crowd instantly, simultaneously put their own hands in the air and wail in unison. She truly is a powerful magician.

6.10pm: Ralph Fiennes is taking questions from the fans at home. "Was it strange to see yourself without a nose?", asks one. "It's strange to see myself WITH a nose" says Ralph. Tomorrow morning's headline sorted.

6.16pm: Mark Williams doing comedy-incompetence. Helena Bonham Carter unnerved by seeing her hat on such a big screen.

6.19pm: "Like everybody she's just really really scared inside": HBC talks Bellatrix.

6.21pm: Someone once screamed in fear at the mere sight of HBC in Hampstead.

6.22pm: She once fell off a table. She's pleased she will never get a wand blister again.

6.24pm: Severus Snape is in the house, aka "Adenoidal Alan"

6.29pm: David Thewlis is not looking forward to seeing the film.

6.29pm: Touch of the Stringfellow to Alan Rickman's haircut. Crowd going wild for one of the most Satanic characters in the film.

6.30pm: Some luvvie-ish backstage chat from Alan Rickman.

6.32pm: Daniel Radcliffe says it's likely to be his finest role. Rickman replies: "You're only 21. Both of us have got a lot of time ahead of us."

6.34pm: Here are some of those facts to take to school tomorrow:
• There were 588 sets made for all eight films
• 58 people worked full-time for 10 years
• They had 35 babies between them

6.35pm: Daniel Radcliffe is on his way. "I imagine London will erupt."

6.36pm: Daniel Radcliffe has arrived. London remains intact.

6.39pm: More stats to swap for lunch money: Daniel Radcliffe got through 160 pairs of glasses during the filming and wore out 60 - 70 wands.

6.41pm: Alex Zane chatting to Daniel Radcliffe. "This is pretty damn cool." Sirens wail in the distance. Remarkably un-film-star-ish, Radcliffe, in his enthusiasm and his disregard for conventional notions of cool.

6.44pm: Radcliffe pleased with his performance in this last instalment: "At last you've done something half decent."

6.45pm: Radcliffe prepped for the Voldemort battle scenes by psyching himself up with Radiohead.

6.46pm: Radcliffe's favourite memory is Gary Oldman teaching him the bassline to 'Come Together' when he was 14.

6.47pm: "You've got JK Rowling here ... I might've been trumped." Radcliffe's last word tells it how it is. Remarkable at a film premiere for the main event to be an author.

6.49pm: Nice Rowling quote: "At last I can come clean... I always knew I would be standing in Trafalgar Square with people chanting my name. And I wasn't even called JK then."

6.50pm: "It's my baby and if I want to take it out and play with it again I will." Rowling leaves open the possibility of more Potter …

7.03pm: And so it is now over: the cast and crew are ambling over to Leicester Square, the fans are pottering home, and the live video stream is looping back over old footage.

We'll leave you with Ryan Gilbey's retrospective piece in tomorrow's Film & Music looking back over the franchise that's dominated the UK film industry over the past 10 years.