Luke is wracked with insecurity after he decides to take early admission to Oxford University. As the day of his departure from Bannerman Road looms, he finds himself dreaming for the first time ever. But what he experiences are terrible nightmares, which play upon his worries about leaving his home, mum and friends behind. These dreams are actually the work of an entity which calls itself the Nightmare Man, who is feeding upon Luke's fears in order to manifest in the real world. Once the Nightmare Man walks the Earth, he will plunge all humanity into an eternal state of bad dreams...

On June 12th, 2009 the production team for The Sarah Jane Adventures held a meeting to begin formally planning the programme's fourth season, which was intended to air in 2010. A major consideration was that Tommy Knight, who had played Luke Smith since the show began, had decided to step back from the series to concentrate on his education. Knight had already taken a reduced role during the third season while studying for his GCSE examinations, and found the experience gruelling; as such, Luke would appear in only two stories for the 2010 season. This would be the second time that The Sarah Jane Adventures had lost one of its young stars due to the demands of their schooling; Yasmin Paige, who had played Maria Jackson when the programme debuted in 2007, had left early in the 2008 season for similar reasons.

Luke would not be the only character whose involvement in the fourth season would be diminished. K·9 had appeared only briefly in 2007 and not at all in 2008, but a new arrangement had been reached which allowed the robot dog to take on a more substantial role in 2009. However, co-creator Bob Baker's independent series K·9 was set to debut on the Disney XD channel on October 31st, 2009, in advance of a full launch on April 3rd, 2010. As such, Baker asked that the character's appearances in the new season of The Sarah Jane Adventures be curtailed. It was therefore decided that K·9 would leave with Luke, who would move away from home to attend university after writing his A Level examinations a year early. This would also play into a larger theme for the season, in which the maturity of the young characters would become increasingly recognised.

The story was originally set at Oxford University, with Luke and other undergraduates battling an otherworldly menace

The original plan for the fourth season was to kick things off with a traditional serial, which would serve as a last hurrah for the established Bannerman Road gang. This was to be handled by lead writer Phil Ford, and involved a woman who would turn out to be an ancient Mayan priestess. The second story -- referred to as “Luke's Leaving Story” -- was assigned to Joseph Lidster, who had written 2008's The Mark Of The Berserker and 2009's The Mad Woman In The Attic. It would be set at Oxford University, and see Luke forge an uneasy alliance with other undergraduates to battle an otherworldly menace -- either an alien con-man posing as a Dean, who had brought a swarm of extraterrestrial flies to Earth, or an ancient destroyer of worlds which was trapped inside a statue and was revived by a misguided student. Luke would save the day, and viewers would be left assured that he would go on to have adventures with his new friends at university.

As the two stories progressed in September and October, however, both Ford and Lidster started to run into problems. Ford found that his serial was just biding time until Luke's departure; much like Maria had exited in 2008's first serial, he began to realise that Luke's departure needed to happen in the season premiere. Lidster, meanwhile, was struggling with his scripts' large cast of characters, and he was having difficulty figuring out how to showcase Luke. Furthermore, the university setting was not gelling properly, leading Lidster to conclude that the story needed to be about the lead-up to Luke moving away, and not its aftermath. As such, it was decided that both Ford's and Lidster's ideas would be scrapped, with the two writers starting afresh. The production team still wanted Lidster to handle “Luke's Leaving Story” due to his skill with emotional elements of the narrative, so it was agreed that Lidster would now write the year's first serial, and Ford the second.

On October 8th, Lidster suggested seven potential ideas for the premiere, of which “A Nightmare On Bannerman Road” was received the most warmly. Inspired by the 1984 horror film A Nightmare On Elm Street, in which deceased child murderer Freddie Krueger haunted the dreams of a neighbourhood's teenagers, it involved a spate of coma patients arriving at a hospital where Clyde was nursing a fractured ankle. The culprit was the Nightmare Man, an entity which had lurked beneath Ealing for aeons and was nourished by bad dreams. Sarah Jane, Luke, Clyde and Rani were all tortured by nightmares, but Luke was emboldened by the glimpse of his future which he had experienced in The Mad Woman In The Attic, enabling him to escape the Nightmare Man's influence and trap the alien in his mind.

A nightmare version of Sarah Jane's funeral included K·9 reciting The Lord Is My Shepherd

Lidster was asked to develop his ideas further, with a direction to drop the hospital setting. For a time, the storyline -- now known as The Nightmare Man -- included the eponymous entity's opposite, the Friendly Man, for whom pleasant dreams were sustenance. At the end of the story, the Friendly Man would convince a furious Luke not to destroy the ensnared Nightmare Man by again appealing to the events of The Mad Woman In The Attic. The other major changes were to the various nightmares experienced by the main characters. Sarah Jane was to have a dream in which an adult Luke confronted her about not being allowed to go off to university. Rani's nightmare originally saw her threatened with punishment at a school where Luke was the headmaster and Sarah Jane was a teacher. A subsequent version involved her being too preoccupied with the rest of her life to help Sarah Jane, Luke and Clyde. Lidster also conceived of a nightmare version of Sarah Jane's funeral, with K·9 reciting the psalm The Lord Is My Shepherd.

Meanwhile, The Sarah Jane Adventures was undergoing a considerable shift in its production personnel, with executive producer Russell T Davies as the only constant. Executive producer Julie Gardner had now completed her move to BBC America, and was no longer involved with the show. Producer Nikki Wilson had joined Doctor Who in the same capacity, and consequently she could not oversee the day-to-day running of The Sarah Jane Adventures. It was decided that Wilson would take the place of executive producer Piers Wenger, enabling him to concentrate more on Doctor Who and his other duties as Head of Drama for BBC Wales. Brought on board as the programme's new producer was Brian Minchin, who had already worked in this role on the 2009 Comic Relief special From Raxacoricofallapatorius With Love....

On March 4th, 2010, the BBC announced that The Sarah Jane Adventures had been renewed for not one, but two further seasons. While this was, in part, a reflection of the excellent ratings earned during 2009, it was also a budgetary decision, since season four would be filmed alongside half of season five. The resulting financial flexibility would permit a return to the production schedule of the first two seasons, which had generally been made in blocks which each consisted of four episodes (two stories). By contrast, the third season had been filmed serial by serial, at a breakneck pace.

Playing the Nightmare Man meant that Julian Bleach had featured as a villain on all three programmes in the Doctor Who family

However, the notion of alternating between two directors was retained from the previous year. The first block -- consisting of The Nightmare Man and Ford's new adventure, The Vault Of Secrets -- was assigned to Joss Agnew, who would also handle the third block. Agnew's most recent credit on the series was Mona Lisa's Revenge. Cast as the titular Nightmare Man was Julian Bleach. Apart from stunt performers and monster artistes, this gave Bleach the unique distinction of having featured as a villain on all three programmes in the Doctor Who family: he had already played the Ghostmaker in the 2008 Torchwood episode From Out Of The Rain, and then Davros in the same year's Doctor Who finale The Stolen Earth / Journey's End.

Recording for the fourth season of The Sarah Jane Adventures began on March 29th, the first of three days at Upper Boat Studios. The middle day was devoted to scenes in Luke's bedroom, bookended by filming on the attic set. On April 1st, material at Park Vale Comprehensive was taped at Cardiff High School. This was followed by three days -- the 2nd, 5th and 6th -- at Clinton Road, which represented Bannerman Road as usual. Also on the 5th, Sarah Jane gave Luke her old Volkswagen Beetle at a garage off Cwrt-y-Vil Road.

Agnew's team then spent several days concentrating on The Vault Of Secrets. Scenes filmed for The Nightmare Man during this period included Clyde and Rani walking to school along Salisbury Avenue in Penarth on April 13th, and the opening confrontation with the Slitheen at the Johnsey Estates in Pontypool's Mamhilad Park Industrial Estate on the 15th. Cast and crew returned to the Johnsey Estates on April 19th and 20th, this time for the material set in the school corridor from Luke's bad dreams. Another nightmare location was Forte's Cafe in Barry, which became the diner where Clyde toiled on the 21st. The rest of The Nightmare Man was completed at Upper Boat, including sequences in the Chandra home on April 22nd, those in the BBC news studio and the black void on the 23rd, and various pick-up shots on the 29th.

The broadcast schedule for the new season was an amalgam of the models used over the preceding three years. Like the 2009 season, The Sarah Jane Adventures would air twice-weekly, so that an entire serial would unfold over consecutive days. As with the 2007 and 2008 seasons, however, each episode would premiere on the CBBC digital channel, before being repeated on terrestrial television. The delay between the two broadcasts would be shorter than in the past, however: the CBBC transmissions would take place on Monday and Tuesday, with the repeats on the Wednesday and Thursday of the same week. Generally, the rebroadcasts were screened on BBC One, but live coverage of the Commonwealth Games shifted The Nightmare Man to BBC Two. Each episode of the fourth season was prefaced by a special trailer in which Clyde introduced the premise of the series; this was essentially the same as for the 2009 season, but with footage from new episodes intermixed. It greeted CBBC viewers when Episode One of The Nightmare Man aired on October 11th.

• Doctor Who Magazine Special Edition #28, 13th July 2011, “Episodes 4.1/4.2: The Nightmare Man” by Andrew Pixley, Panini Publishing Ltd.