English-born Jess is played by Irish actress Ruth Kearney. Oddly fellow Irish actor Ciarán McMenamin gets to keep his own heavy Stroke Country accent while Kearney doesn't keep her southern Irish accent, perhaps because the showrunners didn't want to open up a can of worms by introducing a foreign character (and thus imply that knowledge of the The Masquerade had spread beyond the British government).
Also in Season 4 we have another Irish actress (Ruth Bradley) playing a Londoner (Lady Emily Merchant.)
Many of the incidental/supporting cast were Irish, their RP varying wildly. Notably the submariners in 4.02 and April, who would probably have been less of a ham if Janice Byrne had been kept her natural accent.
Flip Flop of God: The decision of the genus for the Raptors seen in the series has gone back and forth between the show's creators right up until Series 5. Comments alternated between them being Velociraptors or Utahraptor (which was mentioned by Helen Cutter in the first series). After a while they eventually settled on saying they were based on Deinonychus, which is the closest approximate match the Primeval Raptors have for a real life equivalent in terms of appearance and size. And now it's decided that they're Dromaeosaurus instead... meaning they changed their minds to make for a less accurate depiction.
Before Andrew Lee Potts/Connor Temple was the Mad Hatter of Alice, directed by Nick Willing in 2009, Jason Flemyng/Danny Quinn was a flamboyant Knave of Hearts in Alice in Wonderland, a TV-movie directed by Nick Willing in 1999.
Abby and Connor's actors are a couple in Real Life (and are slowly inching to it in the show).
Lester and Christine are also married in real life. Yep. The best part about the Lester/Christine one is that it was completely unintentional. According to the actress, Belinda Stewart-Wilson: "I had been to a few meetings and at one, the director said, 'Do you realize that you will be playing opposite Ben Miller?... Do you know Ben Miller at all?' 'Well, I AM married to him'." ... Uh, not anymore, apparently... sort of... they're seperated, but not divorced.
What Could Have Been: Adrian Hodges had wanted Gary Oldman (an established fan of the show) for the role of Phillip Burton. Now Alexander Siddig was good and all, but can you imagine an A-lister on Primeval?!
Tim Haines and Adrian Hodges attempted several times to make a Primeval movie but failed each time, as they either could not get the appropriate funding or were scrapped due to the executives hoping to meddle with the script. On one occasion the executives at one studio were interested in making the movie and it seemed like the movie was going to be produced when a meeting with the execs was next called. It didn't go very well, as Haines recalls: "Universal, at one point, wanted to make the Primeval movie and were prepared to put the money up so long as Adrian and I agreed to an all-star American cast. For some insane reason I said, 'No.' I said we had to use the British cast. They said, 'How about a compromise? What about using British movie stars instead?' I laughed and said, 'Like who?' This is true. I swear this is true. This is true. I swear this is true. They said, 'How about... Robert Pattinson? He could be Stephen. And what's Liam Neeson doing these days? He could play Cutter.' I thanked them for their time and ran from the building."
Speaking of the Primeval movie, several treatments were drawn up that sound incredibly fascinating:
The first attempt to make a movie, titled Rebellion, was pitched in 2006 (when the series was still in early production), with Tim Haines and Adrian Hodges writing and producing with Ridley Scott rumored to direct. It was a prequel to the series, set in the Roman era, thousands of years before the series. A former centurion who was sold into slavery (Christopher Eccleston and Hugh Jackman were considered for the part) is bought by a Roman and befriends a dinosaur that was made to fight in the arena. Together they would lead the slaves to revolt against the despotic Emperor Nero (with Gary Oldman in mind for the role), basically making the film Gladiator with dinosaurs. Framestore was attached to the effects and Danny Elfman was going to score, but the project was cancelled after Ridley Scott dropped out.
They reworked the idea in 2007 into a Victorian setting starring Charles Darwin, who would have been played by Simon Pegg, finding an ape-man and bringing it back to England, in order to prove his theory of evolution. He shows it to the scientific community, particularly his rival Richard Owen, who orders it handed over to him for study (meaning vivisection). Darwin, who has grown attached to the animal, recruits one of Owen's maids (who would have also served as Darwin's Love Interest), Lance Montgomery (a stereotypical Great White Hunter, who owes Darwin a favour after "that incident in Manila") and a Dutch sailor to help him smuggle the ape-man out of Britain, with Peter Jackson in mind to direct. But a rotation of Warner Bros. execs shut this project down..
Taking off Cuaron's idea, Tim Haines and Adrian Hodges wrote the ultra-violent and deliciously bizarre Primeval script in 2008. A movie adaptation of the series, Primeval opens with a disgraced scientist named Dr Robert Plant being approached by the ARC team (due to his theories about the anomalies) and asked to join them. When a cult called The Children of Time open an anomaly to Africa 102,000 years in the past to locate the "mitochodrial Eve" and kill her so that the human race ceases to exist. A team (including Plant) travel through the anomaly to find her before the cult do and prevent their plans from happening. They find that "Eve" is a child named "Aiv" (pronounced "Eve"). In the end, the team succeed, ensuing the survival of humanity 102,000 years later. Matt Damon signed to play Plant, Framestore was doing the effects, Michael Bay was directing and $100 million was allocated to start filming immediately. But in the last moment, executives decided that the script could be "improved" with comedy, and demanded in particular that the team saw a group of early humans trying to play baseball and they taught them to do it properly. Haines refused, the execs fired him, everyone else quit and the project went back into Development Hell. However, parts of it were used for Helen Cutter's plan in the Series 3 finale.
Tim Haines and Adrian Hodges wrote a more comedic and kid-friendly script in 2009. The film (which Bay was still attached to direct) would open with several enormous anomalies opening all over the planet, letting through Future Predators and a swarm of Megaopterans, who would promptly proceed to overrun the Earth. The ARC team travel through an anomaly to the creature's home time in order to find a way to defeat them, and what followed was very much like Mad Max, with Future Predators and Megaopterans hunting humans in a post-apocalyptic world. The team would discover that the catastrophe that created this world was the one they travelled to this era to prevent. They also discover a way to destabilise anomalies, trapping the Future Predators and Megaopterans in their dying world. The film would end with a surviving group of Future Predators and Megaopterans hiding in the present day.
James Cameron took the helm as producer in 2009 and went back to the idea of making an movie adaptation of the series, but refused to write or direct as he was too busy doing Avatar. The treatment called for the use of stock-footage of the original Primeval series, with narration from Lester. The Masquerade has broken wide open, with the ARC being a semi-famous organisation that monitors the use of the time travel. The script then cuts to the protagonist (whom Mark Whalberg was attached to play), an ARC soldier, and follows him as he discovers a plan to harvest natural resources from the past. Michael Bay was at one point attached to direct the film, which would have included some large-scale action sequences. Universal rejected the treatment, however, and Bay and Cameron dropped out.