Starring Matthew Macfadyen, Keeley Hawes, David Oyelowo, Jenny Agutter, and Peter Firth, the initial series of six one-hour episodes premiered in the spring of 2002.

The series was a critical and popular success, averaging 7.5 million viewers over its six episodes, due to its combination of glossy high production values with fast-paced action/adventure and spy intrigue storylines.

The show quickly gained an unexpected edge with the violent killing of character Helen Flynn (Lisa Faulkner) in the second episode which drew the largest number of complaints to the Broadcasting Standards Commission in 2002. During an undercover operation Helen and Tom were captured by race riot instigator Robert Osborne, played by Kevin McNally, who tortured Helen with a deep fryer in an attempt to make her superior Tom reveal classified information. He refused and she was killed. This provoked an angry reaction from many viewers who jammed BBC phone switchboards with complaints, despite the show airing after the 9 pm watershed. Nevertheless the death of Faulkner's character set the precedent that in Spooks anyone can die