In pursuit of the Daleks who were working with the Master, the TARDIS materialises on Spiridon. Jo leaves the unconscious Doctor behind while she ventures into a hostile jungle, where she encounters a group of Thals. Returning to the TARDIS, they reveal to the now-recovered Doctor that their mission is to locate and destroy an army of ten thousand Daleks, hidden somewhere on Spiridon. Poisoned in the jungle, Jo is saved by Wester, one of the planet's invisible natives. The time travellers discover that the Daleks intend to learn the secret of the Spiridons' invisibility, rendering their army virtually unbeatable...

In early 1972, Doctor Who producer Barry Letts and script editor Terrance Dicks developed plans for the programme's celebratory tenth season. They wanted to include an epic story which would rival in length the twelve-part The Daleks' Master Plan from 1965. However, when concerns arose that the audience might not tolerate a serial running for three months, it was decided to split the narrative between two six-part adventures. Each story would feature one of the Doctor's two greatest foes: first the Master, in Malcolm Hulke's Frontier In Space, and then the Daleks.

The Daleks had returned to Doctor Who after a lengthy absence in Season Nine's Day Of The Daleks. That serial's development had brought Letts and Dicks in touch with the monsters' creator, Terry Nation. Nation had not written for Doctor Who since The Daleks' Master Plan, and his last contact with the show's production team had been in 1967 when he refused permission for a story in which the Daleks appeared alongside the Cybermen. In obtaining Nation's authorisation for the Daleks' return in Day Of The Daleks, Letts and Dicks had agreed that the writer would be granted the right of first refusal to script future Dalek stories.

The Thals, invisible aliens and deadly jungle environment drew from Terry Nation's Sixties Dalek serials

As it happened, the production team's inquiries about a Dalek story for Season Ten coincided with a lull in Nation's workload, and so he elected to tackle it himself. A storyline was commissioned under the title “Return Of The Daleks” on April 21st. Nation drew upon his Sixties Dalek serials for ideas: the Thals had been introduced in 1963's The Daleks, while The Daleks' Master Plan had featured both invisible aliens and a deadly jungle environment. The serial was soon retitled Planet Of The Daleks, and then became “Destination: Daleks” when the scripts were commissioned on May 11th.

One of Nation's guest characters, Rebec, was named for his daughter, Rebecca. Another of the Thals, Petal, was anagrammed to Latep to avoid confusion with Patel from Frontier In Space. The planet was called Destinus before becoming Spiridon. In Episode Six, Nation introduced a Supreme Dalek, partly as a response to the Dalek Emperor conceived by David Whitaker for 1967's The Evil Of The Daleks, which Nation had disliked. Unlike earlier Dalek authority figures, which had borne a primarily black colour scheme, the Dalek Supreme was described as sporting a black and gold livery. Plans to kill off all the Thals at the end of Episode Four were abandoned, in part due to concerns about the reaction of Ronnie Marsh, the Head of Serials. Also dropped were the individual episode titles Nation introduced, having been unaware that their use in Doctor Who had been discontinued in mid-1966. Latterly, Dicks made several changes to Episode One to bring it in line with the revised ending of Frontier In Space, in which the Doctor was shot by the Master.

Assigned to direct “Destination: Daleks” was David Maloney, whose last Doctor Who work had been on The War Games in 1969. The three Dalek casings used for Day Of The Daleks and Frontier In Space, assembled from surviving elements constructed during the Sixties, would again be the primary Daleks in “Destination: Daleks”. The gold-coloured Chief Dalek was repainted in grey to match its two brethren. Nation had been unsure how many Dalek casings would be available to the production team. As a result, the limited number imposed some changes on the scripts, such as by having only Rebec masquerading as a Dalek in Episodes Five and Six; Nation had envisaged Codal doing likewise, rather than concealing himself within Spiridon furs.

In addition, seven new Dalek casings were constructed by Pinewood-based Westbury Design and Optical, run by visual effects designer Clifford Culley. Maloney was disappointed to discover that these were of generally inferior workmanship, however, having been predominantly made from wood rather than fibreglass. As such, these so-called “goon” Daleks would be kept in the background as much as possible. For the Dalek Supreme, Nation agreed to loan the production a refurbished casing he had been given by Aaru Pictures, following its appearance in their 1966 feature film Daleks: Invasion Earth 2150 AD.

Just before location filming began, the title of the story reverted to Planet Of The Daleks, due to Barry Letts' concerns that “Destination: Daleks” lacked a sense of intrigue. The only venue required was Beachfields Quarry in Redhill, Surrey, which had just been used as the surface of the Ogron planet in Frontier In Space. This time, it was the site of the ice pool on Spiridon, with recording taking place on January 2nd and 3rd, 1973. This work was followed by four days at the BBC Television Film Studios in Ealing, London: January 4th, 5th, 8th and 9th. Here, Maloney concentrated on sequences in the chimney and the ice tunnels. Model shots of the TARDIS were captured on January 16th.

As usual, studio recording for Planet Of The Daleks took place fortnightly, on Mondays and Tuesdays. Shortly before this phase of the production began, Katy Manning had her hair cut, meaning that Jo's appearance somewhat differed between the filmed and videotaped sequences. The first studio block took place on January 22nd and 23rd at BBC Television Centre Studio 4 in White City, London. The Monday saw the completion of most of Episode One, along with the material outside the TARDIS and in the console room for the end of Episode Six. Maloney also recorded new material for the concluding installment of Frontier In Space. The Tuesday was then devoted to Episode Two. More model filming was carried out on January 27th and 29th, for the ventilation shaft and the ice tunnel, respectively.

The second studio block took place on February 5th and 6th, this time in TC6. Maloney used the Monday to record Episode Three, along with the Dalek control room sequence for Episode Two. The Tuesday was spent on Episode Four, plus material in the rocky area for Episode Six. On February 8th, the footage of the Dalek army was filmed at the BBC Television Centre Model Stage (formerly the Puppet Theatre). A remount had to be performed the following day when it was realised that the hand of an effects assistant was visible in some shots. Planet Of The Daleks was completed on February 19th and 20th in TC1. The Monday centred on Episode Five, but also saw the recording of scenes at the city entrance for Episode Three, the chimney parapet for Episode Four, and various effects shots. The Tuesday then focussed on Episode Six.

With Episode 1, Doctor Who reentered the week's Top Ten programmes for the first time since 1965

On April 7th, Planet Of The Daleks Episode One aired twenty minutes later than usual, at 6.10pm. It was preceded by the news and, before that, an extended edition of Grandstand which featured the 119th running of the Boat Race between Cambridge and Oxford Universities. The usual Tom And Jerry short was dropped that evening, so Doctor Who was immediately followed by the High Adventure movie strand. Nonetheless, the broadcast saw Doctor Who reenter the week's Top Ten programmes for the first time since another Dalek serial, The Chase, in 1965.

More scheduling shifts impacted the remainder of Planet Of The Daleks. Over the next two weeks, the news update was preceded by another bonus-length Grandstand and then the Oscar Wilde cartoon The Selfish Giant. The timeslot's ostensible occupant, We Want To Sing, aired in front of Episodes Four and Six but it was again displaced before Episode Five on May 5th, this time by The Pink Panther. Meanwhile, High Adventure had given way to the comedy film Who's Minding The Mint? after Episode Three on April 21st, which was also the final night that a Tom And Jerry short was used to bridge from Doctor Who into the subsequent programme. The Wonderful World Of Disney made a brief return on April 28th. As of May 5th, Doctor Who now led into the Jimmy Savile programme Clunk-Click.

• Dalek 63·88, edited by Jon Green and Gavin Rymill.
• Doctor Who Magazine #202, 4th August 1993, “Archive: Planet Of The Daleks” by Andrew Pixley, Marvel Comics UK Ltd.
• Doctor Who Magazine Special Edition #2, 5th September 2002, “Saturday Night's Alright For Fighting” by Andrew Pixley, Panini Publishing Ltd.
• Doctor Who: The Complete History #20, 2016, “Story 68: Planet Of The Daleks”, edited by John Ainsworth, Hachette Partworks Ltd.
• Doctor Who: The Handbook: The Third Doctor by David J Howe and Stephen James Walker (1996), Virgin Publishing.
• Doctor Who: The Seventies by David J Howe, Mark Stammers and Stephen James Walker (1994), Virgin Publishing.