Why Doctor Who filmed the Highlands in West Sussex

A fan-favourite Doctor Who adventure is being released on Blu-ray for the first time with updated special effects 50 years after it was filmed with West Sussex doubling up as the Scottish Highlands.

Terror of the Zygons was broadcast in four parts between 30 August and 20 September 1975.

It featured Tom Baker as The Doctor at the start of his second season in the role and was filmed on location in Climping, South Ambersham, Storrington, Charlton and Crabtree.

Richard Bignell, Doctor Who historian, said it was "an excellent adventure, which is helped by some truly stunning location work".

He added: "The BBC's production budgets for Doctor Who were always somewhat meagre, so taking the cast and crew up to Scotland to film was never really going to be a possibility.

"The locations chosen in West Sussex to double for the environs around Loch Ness were superb and apart from the lack of mountains, you'd be hard-pressed to tell that it wasn't shot in the Highlands."

Filming for Doctor Who in the 1960s, 70s and 80s often took place in the counties closest to London, whether featuring an alien landscape or, in this case, the Scottish Highlands.

Speaking to BBC South Today at Climping on 18 March 1975 Tom Baker said: "We were looking for a place within striking distance of London where there was a landscape and seascape which would allow us to generate the suspense, tension and excitement that our stories are all about.

"It's as simple as that - it's a lovely place to be."

The adventure introduced the Zygons who returned for the show's 50th anniversary in 2013

Filming took place outside the Fox Goes Free pub in the village of Charlton in March 1975.

It proudly displays a photo of the cast in its bar and still has Whovians - the name commonly given to Doctor Who fans - from far and wide visiting to see where the show was filmed.

Sharon Ford, deputy manager, said: "It is a great piece of history for the pub and customers are always intrigued."

Alex Nicholls was 12 years old in March 1975 when she spotted filming at Furnace Pond in Crabtree.

She told BBC South in 2004: "It was meant to be Loch Ness and they were filming some kind of monster that was meant to be coming out of the lake.

"It was the Easter holidays and I had to bite my lip for a few weeks before I could go back to school and tell everyone."

Tom Baker wore Highland garb on location in West Sussex to film Terror of the Zygons

The adventure introduced the Zygons, large red shape-shifting aliens with suckers, who returned for the show's 50th anniversary in 2013.

It has always been considered a fan-favourite, featuring Tom Baker at his most authoritative once he had settled into the role of the Time Lord.

Terror of the Zygons is part of Doctor Who: The Collection - Season 13 and is released in October.