I'd like to think the show is still one of the most imaginative on television

Chris Carter

It made stars of David Duchovny and Gillian Anderson as FBI agents Mulder and Scully, and helped establish the Fox TV network as one of the biggest in the US.

But Mr Carter, who invented the concept of the series, said that he wanted the show to finish while it still had creative vitality.

"We want to go out on top - we wanted to go out as a strong show," he said after confirming the decision on Wednesday.

Mr Carter also praised the recent additions to the cast, Annabeth Gish, and Robert Patrick who replaced David Duchovny as a lead agent in the series.

"I'd like to think the show is still one of the most imaginative on television," he said.

Quality drama

The Fox Entertainment Group chairman Sandy Grushow said that the show had "helped define the network".

Mulder and Scully helped establish Fox TV

"It alerted the industry to the fact that we could succeed with a quality drama," he said.

Mr Grushow called Mr Carter "so inspiring" and said: "He created a television series not just for our times, but for all times."

Mr Carter says that he has not started writing the series' 201st and last episode, which will be a two-parter - but said that he hoped David Duchovny might return for it.

A second feature film is also in preparation at Fox.

The X-Files, shown on Sky One and BBC Two, also attracted a cult following in the UK.