Primeval is a British science fiction television programme produced for ITV by Impossible Pictures. Created by Adrian Hodges and Tim Haines, who previously created the Walking with... documentary series. Primeval follows a team of scientists tasked with investigating the appearance of temporal anomalies across Great Britain through which prehistoric and futuristic creatures enter the present.

 First broadcast in the UK on 10 February 2007, it has since expanded to an international audience. Overall reception of the programme was positive during the first and second series, maintaining a 25% audience share in the United Kingdom during both series to date. Before it was broadcast on 9 August 2008 on BBC America, the programme received generally positive reaction from American critics as well. The third series, which ITV announced on 30 January 2008, began on 28 March 2009. In the US, series 3 premiered on 16 May 2009 on BBC America.

 On 29 September 2009, it was announced that a deal had been struck between ITV, BBC Worldwide, Watch, Impossible Pictures and the German broadcaster ProSieben to produce two new series of the show for transmission in 2011.

 Five webisodes were announced prior to the fourth series of seven episodes, which started airing on New Year's Day 2011 on ITV (ITV1/STV/UTV) in the UK and on BBC America in the US. The fifth series of six episodes aired on Watch in May 2011 and will be repeated on ITV later. Impossible Pictures has made no announcements about the show's future since production of Series 5 wrapped in November 2010. A Canadian spin-off, titled Primeval: New World, was announced on 15 September 2011, with production beginning in the winter.

Series 1 followed the efforts of Professor Nick Cutter (Douglas Henshall) and his associates, a friend and colleague Stephen Hart (James Murray), a student Connor Temple (Andrew-Lee Potts), a zookeeper Abby Maitland (Hannah Spearritt) as they investigate the appearance of anomalies (called "earthquakes in time") that allow the passage to other times and places, allowing often-dangerous creatures from the distant past or future to threaten the lives of citizens. The British government's Home Office, under the supervision of James Lester (Ben Miller) and Claudia Brown (Lucy Brown), becomes involved after a Gorgonopsid travels through one such anomaly and wreaks havoc in the Forest of Dean. Professor Cutter's wife, Helen Cutter (Juliet Aubrey), presumed dead for eight years, was revealed to have been travelling in time through the anomalies. Cutter was unable to convince her to help as she had changed much from the woman he had once known, and he began to fall in love with Claudia. Meanwhile Abby began to take care of a Coelurosauravus she named Rex after he was left behind in the present, and was attracted to Stephen, who didn't completely reciprocate her feelings, despite Connor's attempts to get with her. The final episode of the first series involves discovery of an anomaly to the future in the Permian, allowing Predators from the future access to the past, and ultimately the present. Cutter, who travelled through an anomaly with Helen, came back to help with the predators and attempted a mission to secure the anomaly so that the future predators couldn't change the time-line, but ultimately failed. Upon returning he discovered Stephen had once had an affair with Helen before she had disappeared, and then learned that Claudia Brown never existed as the time-line had changed very slightly after their trip, and only he and Helen were aware of it.

Series 2 established that the camp discovered in the first episode was actually that of the team and that they had created their own past. Due to Cutter and Helen's visit to the camp, they affected the time-line, although this was the second time at the camp (the first was finding the camp, the second time years or months earlier setting up the camp so it can be found by them later), which had resulted in the disappearance of Claudia Brown from the time-line. In her place an assertive and quite different PR agent named Jenny Lewis joined the team in the Anomaly Research Centre or ARC, a building in the new time-line that deals with researching the anomalies. Having fallen for Claudia, a distraught Cutter was forced to start again with her look alike while Connor gained a girlfriend, Caroline Steel (Naomi Bentley), a woman with a hidden agenda whom Abby despised, but the two were drawn closer by an encounter with Mer Creatures. As Stephen and Cutter tried to repair their friendship, Helen also returned and began rekindling her friendship with Stephen, and eventually their affair. Taking Claudia's previous position was a man named Oliver Leek (Karl Theobald), who secretly worked with Helen to use the anomalies to gain political power by gathering some of the creatures the team had encountered, and also controlling the future predators, using an unwitting Caroline to steal Rex for him. The team were also faced with an unusual man (Tim Faraday) whom they first encountered as a cleaner and who worked against the team before he was killed in the Silurian by a Silurian Scorpion. The final conflict of the season resulted in the deaths of Stephen, who died to save the lives of the rest of the team, and Leek, who was torn apart when he lost control of his creatures.

 Series 3 found Cutter continuing to investigate anomalies and attempted to find ways of predicting them with the help of Stephen's replacement on the team, Captain Becker (Ben Mansfield). Meanwhile Lester had to deal with an old rival Christine Johnson (Belinda Stewart-Wilson), an unscrupulous government official who hoped to obtain the power of the anomalies and the Future Predators for military uses. With the assistance of Sarah Page (Laila Rouass), a professor employed at the British Museum, Cutter begins to contemplate the origins of the anomalies based on folklore. Helen tries to invade the ARC with a group of clones of the mysterious cleaner. Cutter takes an artifact from Helen, and is shot and killed by her in the process. Connor obtains the artifact and discovers that it was in fact a map to predict anomalies. However, they are not able to get it to work, but they do manage to create a device to lock anomalies and prevent creatures coming through. Danny Quinn (Jason Flemying), a former police detective who became involved after discovering his brother had been killed by a creature from the future, becomes the team leader following Cutter's death, while Jenny departs after having nearly died. Connor and Abby's relationship grows, despite her brother Jack moving into her flat and going through an anomaly to the future. Helen returns near the season's end, with a device that opens anomalies at will, revealing that she will go back to eradicate the human race by killing the first hominids. She kills Christine and travels back to the future, followed by Danny, Connor and Abby. While Abby and an injured Connor are forced to remain in the late Cretaceous Danny catches up with Helen in the prehistoric past and Helen is killed by a raptor that had followed Danny into the Pliocene. The anomaly closes on him, leaving him trapped in the Pliocene and Abby and Connor trapped in the Cretaceous.

 Series 4 was preceded by five webisodes which partially bridge the year that has passed. New team members are introduced, and intrigues are set up, with Sarah having been killed in one of several attempted rescue missions led by Captain Becker. The ARC has been updated and restructured with a new team leader Matt Anderson (Ciarán McMenamin), a man with a hidden agenda with the ARC and the anomalies, Jess Parker (Ruth Kearney), a coordinator for the field team and Philip Burton (Alexander Siddig) an entrepreneur funding the ARC in a public/private partnership with the government.

 Connor and Abby returned from the Cretaceous after finding Helen's dropped anomaly device, which was later eaten by a Spinosaurus that followed them. They were forced to earn their old jobs back by ending the reign of a Kaprosuchus living in the docks, following a new policy established during their disappearance where only people with a military background could work in the field. Later a group of time travellers arrived, including the mysterious Ethan Dobrowski (Jonathon Byrne), and Emily Merchant (Ruth Bradley), who is from the Victorian era. Matt took pity on Emily and kept her in his flat so they could find Ethan together, only for her to be kidnapped by him first, tied up, gagged and placed in a coffin, before being rescued. Meanwhile Abby and Connor's new relationship, formed during their time in the Cretaceous, became strained under their jobs, particularly when Philip threatened to put Rex down and Abby going against him without Connor's support, and Connor agreeing to work for Philip on his own research team. The finale found Danny returning from the Pliocene, and it was revealed that Ethan was in fact his brother Patrick, who had been changed by his experiences through the anomalies. Patrick escaped into the Pliocene with Danny pursuing him, but not before telling Matt that Philip had known Helen. Matt admitted to a departing Emily that he was from the future, sent back to prevent someone interfering with the anomalies and causing the Earth to become uninhabitable along with his father, Gideon (Anton Lesser), who had just died. Meanwhile Connor had done research into anomaly patterns and told Philip that he has discovered the anomalies will grow more frequent until they cause a catastrophe. Philip agreed to help find a solution, but asked that they keep the looming disaster to themselves for the time being.

 Series 5 took place almost immediately after, with Philip recruiting Connor to help in his secret project called New Dawn, which would take energy from the anomalies and use it to solve the world's energy crisis. Matt, now aware Philip was responsible for the end of the world, asked for Abby's help after she figured out he was from the future due to his knowledge of Burrowing insects during an incursion. As they attempted to find out what Connor was researching with his assistant April Leonard (Janice Byrne) the team continued to deal with the anomalies. When Matt ended up in 1868 while trying to recapture a raptor, he encountered Emily and convinced her to return after finding out she would be committed to an asylum by her husband. Soon Connor created the first man-made anomaly in the ARC, however it caused a swarm of Future Beetles to invade the ARC, during which Matt and Abby revealed they were investigating Philip. In the aftermath of the crisis Connor went through Philip's files and discovered he had actually known Helen and had created a larger version of Connor's anomaly machine. Later several anomalies began opening at once as part of Convergance, a natural phenomenon which would change the Earth's magnetic pole from the north to the South, and a Tyrannosaur's rampage made the anomalies public. Philip abandoned Connor to activate New Dawn's anomaly as it required absorbing the energy from open anomalies, and Connor and Abby repaired their fractured relationship. Matt failed to stop Philip as he activated New Dawn and Connor, attempting sabotage, fell through the large anomaly and ended up in the desolate future Matt had lived in. While being rescued, the ARC was invaded by mutated versions of Future Predators, resulting in Lester becoming injured. Philip's anomaly became unstable, and Philip realised Helen had tricked him into wiping out humanity and tried to set things right by imploding the facility with him inside. Connor came up with a plan to use his anomaly to make the larger one unstable, and Matt drove it into the New Dawn anomaly with the intention of fulfiling his mission while sacrificing his own life. The plan worked and Matt somehow managed to survive, with the future changing once again. Abby, having whispered it earlier to Connor during the rescue, proposed to Connor and they became engaged. While the team is alerted to a new anomaly and prepare to head out, Matt encounters another version of himself, warning him to return home.