Mrs Wormwood returns, desperate for Sarah Jane's help. She explains that she is now being hunted by the Bane, due to her failure during their attempted invasion of Earth. In retaliation, she wants to foil the Bane's plan to resurrect an ancient interstellar conqueror named Horath. To do so, she requires information stored in UNIT's Black Archive, and Sarah Jane reluctantly agrees to seek assistance from her old friend, Brigadier Lethbridge-Stewart. But Mrs Wormwood has formed a secret alliance with Sontaran Commander Kaagh. The plan to revive Horath is theirs -- as a first step to their domination of the galaxy.

The first season of The Sarah Jane Adventures was bookended by two stories which featured the same villains -- in that case, the Slitheen, who menaced the Bannerman Road gang in both Revenge Of The Slitheen and The Lost Boy. For the programme's second year, the production team decided to follow a similar format, but with a twist. Not only would the season finale bring back the Sontaran Commander Kaagh -- who had been introduced in the opening serial, The Last Sontaran -- but it would pair him with another returning foe. Mrs Wormwood of the alien Bane had been the show's very first antagonist, in the New Year's Day 2007 special Invasion Of The Bane. In the spring of 2008, actress Samantha Bond confirmed that she was interested in reprising the role.

Lead writer Phil Ford -- who had scripted The Last Sontaran and the year's second serial, The Day Of The Clown -- began developing the finale, which ultimately bore the title Enemy Of The Bane. Given the pairing of the two malefactors, it was suggested that Sarah Jane and her friends should likewise receive the assistance of a friend from the broader Doctor Who universe. Originally, this was to be Freema Agyeman as Martha Jones, who was the Doctor's companion throughout the parent show's 2007 season. She had then returned for a trio of episodes in 2008, having become affiliated with the Unified Intelligence Taskforce (UNIT), and she had made Sarah Jane's acquaintance in the season finale, The Stolen Earth / Journey's End. Martha had also appeared in three installments of Doctor Who's other spin-off series, Torchwood, during 2008, and executive producer Russell T Davies was planning for her to play a more significant role in that spin-off's 2009 season as well.

A replacement for Martha Jones had to be rapidly identified

In May, however, Agyeman was offered a lead role in Law & Order: UK. The new opportunity would leave her unavailable for Torchwood, and while it was hoped for a time that she might still be able to appear in Enemy Of The Bane, on June 15th it was confirmed that this was no longer possible. With just a week to go before the readthrough and two weeks before production was scheduled to begin, this meant that a replacement character had to be rapidly identified.

Within twenty-four hours, the discussion was coalescing around the idea of delving back into Sarah Jane's past, by reviving a familiar face from twentieth-century Doctor Who: Brigadier Alistair Lethbridge-Stewart, played by Nicholas Courtney. One of the programme's longest-serving and most beloved recurring characters, Lethbridge-Stewart had first appeared in 1968's The Web Of Fear, and was then reintroduced as the head of UNIT in The Invasion later that year. Courtney had featured regularly throughout Jon Pertwee's tenure as the Third Doctor, and he was first paired with Elisabeth Sladen as Sarah Jane Smith in her debut story, 1973's The Time Warrior. Courtney's appearances in Doctor Who had gradually diminished after Tom Baker took over as the Fourth Doctor, but the Brigadier was brought back for sporadic appearances during the Eighties, including a new encounter with Sarah Jane in 1983's twentieth-anniversary special The Five Doctors. The two characters also appeared in the thirtieth-anniversary celebration Dimensions In Time in 1993. Since then, Courtney had reprised Lethbridge-Stewart on numerous occasions, including a variety of audio plays for Big Finish Productions. He and Sladen were reunited on projects such as the direct-to-video drama Downtime and the Third Doctor radio plays The Paradise Of Death and The Ghosts Of N-Space.

With Courtney confirming his availability for Enemy Of The Bane, Ford's scripts were hastily rewritten to accommodate the character -- now Sir Alistair, as suggested by the 2008 Doctor Who story The Sontaran Stratagem / The Poison Sky. Nonetheless, it briefly appeared that an additional hurdle might arise in securing permission to use Lethbridge-Stewart from his creators, Mervyn Haisman and Henry Lincoln; fortunately, this issue was resolved without hampering production.

Enemy Of The Bane formed part of the year's third production block, joining The Temptation Of Sarah Jane Smith under director Graeme Harper. Work began on June 26th with a day on the sets for the Chandra residence at Upper Boat Studios, the programme's regular production home. Next, June 30th and July 1st were spent at Trefil Quarry near Tredegar for sequences in and around the stone circle. On July 2nd and 3rd, the Usk Valley Business Park in Pontypool posed as the Lexington Road Industrial Estate. Recording on the 4th began with material in UNIT's Black Archive -- actually the Collection Centre for the National Museum of Wales in Nantgarw -- before Harper's team returned to Upper Boat for various effects shots. Upper Boat was the venue again on July 7th, for scenes in Sarah Jane's attic, as well as Luke's nightmare.

On July 8th, Nicholas Courtney recorded scenes as Lethbridge-Stewart for the first time in the new century, when material at Sir Alistair's home was taped at a house on Marine Parade in Penarth. Later that day, a shop on Cornerswell Road in Penarth was dressed as Gita's florist business, Bloomin' Lovely, and work continued there on the 9th. July 10th, 11th and 14th were spent on Clinton Road in Penarth for material on Bannerman Road. On the 15th, MOD St Athan was used as the exterior of the Black Archive, and also provided a suitable space for Kaagh's pursuit of Luke.

Most of the remaining material for Enemy Of The Bane was completed at Upper Boat, including Major Kilburne watching the security cameras on July 18th, and various attic scenes on the 23rd. The last day of production for The Sarah Jane Adventures was August 1st, which largely dealt with several insert shots, recorded both on Clinton Road and at Upper Boat; the latter work also included additional material in the Chandra residence. However, some pick-up shots were still needed, and they were completed at Upper Boat during filming for Torchwood on September 5th.

On November 25th, the BBC announced that The Sarah Jane Adventures had been renewed for a third season

Editing removed an explanation for Lethbridge-Stewart's use of a cane, with Sir Alistair telling Sarah Jane that he has had a Katta Makhanu stinger in his leg for the last fifteen years, rendering it all but useless. On November 25th, six days prior to the CBBC broadcast of Enemy Of The Bane Episode One, the BBC announced that The Sarah Jane Adventures had been renewed for a third season in the autumn of 2009. The statement also confirmed that Davies would continue to be the programme's executive producer, despite the fact that he would be leaving Doctor Who following a series of specials which were to culminate on New Year's Day 2010. As the second season of The Sarah Jane Adventures wrapped up on December 8th, however, Davies was grappling with the possibility that the budget for The Sarah Jane Adventures might be significantly reduced. The situation was exacerbated by the fact that its 2008 ratings -- while still very good -- were falling short of what had been achieved in 2007, even as Doctor Who was rising to impressive new heights of viewership.

Sadly, Enemy Of The Bane proved to be Courtney's final television appearance as Lethbridge-Stewart. It was hoped that he would return to The Sarah Jane Adventures for the following season's The Wedding Of Sarah Jane Smith, but poor health intervened. Cancer ultimately accomplished what hordes of Daleks and Ogrons, Silurians and Sea Devils had failed to do: Nicholas Courtney passed away on February 22nd, 2011, leaving Doctor Who bereft of one of its greatest ambassadors and most popular stars.

• Doctor Who Magazine Special Edition #23, 24th December 2009, “Episodes 2.11/2.12: Enemy Of The Bane” by Andrew Pixley, Panini Publishing Ltd.
• Doctor Who: The Writer's Tale: The Final Chapter by Russell T Davies and Benjamin Cook (2010), BBC Books, ISBN 978 1 846 07861 3.