The British Invasion is the 17th episode of Season 12. It aired on April 6, 2017.
- Jared Padalecki as Sam Winchester
- Jensen Ackles as Dean Winchester
- Mark Sheppard as Crowley
- Mark Pellegrino as Lucifer
- Misha Collins as Castiel (voice only, uncredited)
- Samantha Smith as Mary Winchester
- David Haydn-Jones as Arthur Ketch
- Courtney Ford as Kelly Kline
- Shoshannah Stern as Eileen Leahy
- Ali Ahn as Dagon
- Adam Fergus as Mick Davies
- Gillian Barber as Doctor Hess
- Michael Meener as Dr. Turner
- Darren Adams as Renny Rawlings
- Eric Mazimpaka as Dermott Culp
- Alex Barima as Drexel
- Spencer Drever as young Mick Davies
- Luke Seybold as Timothy
Featured Supernatural BeingsEdit
- Archangel (Lucifer)
- Banshees (mentioned only)
- Crossroad Demon (Crowley)
- Demons (Dermott Culp, Drexel)
- Nephilim (mentioned only)
- Prince of Hell (Dagon)
- Eileen Leahy previously appeared in the season 11 episode Into the Mystic. Renny Rawlings references the events of this episode when he calls Eileen "the Banshee girl" and tells her that they have a file.
- Dagon and Kelly Kline previously physically appeared in Family Feud.
- Lucifer is shown licking the floor in this episode. He had previously forced Crowley to do this in Beyond the Mat.
- The Colt returns to Dean's possession. He had previously used it in Abandon All Hope....
- Castiel's cell phone responds with the same voicemail he had in First Blood.
- The episode had 1.57 million viewers and got a 0.5 rating.
- The title is a reference to the phenomenon that occurred in the mid-1960s when rock and pop music acts from the United Kingdom, as well as other aspects of British culture, became popular in the United States, and significant to the rising "counterculture" on both sides of the Atlantic.
- Much like John during Mary's death, Mary has developed a romantic relationship with someone else, specifically with Arthur Ketch. This makes it the first time she had a sexual encounter with anyone in almost three decades.
- Sam is shown to have a better understanding of sign language.
- Arthur Ketch revealed that he and Mick went to Kendricks Academy together.
- Mick revealed that the key to the bunker can unlock every chapter house in the world.
- Gillian Barber, who plays Doctor Hess, previously played Mrs. Rourke in Faith.
- This is one of the few episodes where a creature capable of teleportation is actually shown doing it on screen, rather than during a shot change.
- Lucifer calls Michael his "little bro". It has previously been established throughout Season 5 that Michael is the older of the two. This same error was made in Hell's Angel, an episode also written by the same writers.
- Mick previously stated that he had not killed anyone before prior to Hayden Foster, but that is contradicted in this episode, as his first kill is shown to be Timothy, his best friend, from Kendricks Academy.
|“||The code is what makes a young boy kill his best friend.||”|
|“||You only have to do what you know is right. You only have to answer to your own code.||”|
|“||You think I wanted this to happen? He used me... but I love this child.||”|
|“||Well, that was unexpected. But invigorating. I must say, when I first met you I didn't see this coming. My thought at the time was, 'I'll end up shooting this one.' Life is full of surprises.||”|