Other mistake: In the "Uncut" version of the film, after the "Dinner Party" at Valentine's place, when Valentine is at the door saying goodbye to Harry, he says "Just give me a couple of days to think over your proposal." His lisp has disappeared on the word "days." (00:57:00)
Character mistake: Galahad claims that classifies Brogues as being 'mutually exclusive' from Oxfords. Broguing is any decorative hole punching on shoes and can be found on any shoe style.
Character mistake: When giving Eggsy a tour, Galahad tells him that Oxfords are any formal shoe with open lacing. This is incorrect as Oxfords have closed lacing.
Visible crew/equipment: When Eggsy is in the car yelling at his mum's boyfriend and the windows start to go up, you can see a man's head next him on the floor.
Continuity mistake: Just before the bar brawl, Harry takes the time to lock and bolt every exit and doors so that there would be no possible escape from his wrath...after all is done, and he is done kicking ass he proudly walks away and right through the front door without unlocking it.
Character mistake: Anyone who knows anything about firearms would never handle a firearm with their finger on the trigger unless ready to shoot. In the training scene with the dog Eggsy is running with his finger on the trigger the whole time. Merlin also does it in the end scene at Valentine's secret lair inside the jet.
Continuity mistake: In the end credits scene, when Eggsy appears in the pub, Dean is holding a pint glass in his hand, but in the next shot, the glass is suddenly on the table.
Other mistake: In the final scenes where Eggy goes to have a fight at the pub with his mother's boyfriend they are listening to Slave to Love by Bryan Ferry. The counter says 962 whilst the tape machine is playing (electronic), but the counter does not change.
Continuity mistake: At the start, the way Harry holds the medal of valor changes between shots. (00:03:20)
