Anomaly

Anomalies are portals in time that form links between eras throughout all of history. They have opened numerous times in numerous locations.

In Primeval
The British government, in the form of the Home Office becomes involved after a Gorgonopsid travels through one such anomaly and wreaks havoc in a subdivision. Helen Cutter, presumed missing in the first episodes, is revealed to have been stuck inside one anomaly for years and is now using the anomalies to try to access the future. The final episode of the first series involves the first appearance of a future anomaly, allowing predators from the future access to the present, and ultimately, the past. Anomalies have opened in many locations and to many different time era's. A well known anomaly opened in The Forest of Dean and lead to the Permian era. Anomalies will return and open in new locations in Series 4 and Series 5.