Space: 1999 was set, as the title suggests, in the year 1999. Moonbase Alpha is a self-contained community for scientific research and deep space exploration. It is also a dumping ground for nuclear waste following a thermonuclear war on the earth in 1987. On September 13th, 1999 a sudden surge of magnetic radiation detonates the waste, hurling the moon out of Earth’s orbit and into a black sun from where it finally emerges hundreds of light years from our own galaxy.

Alpha’s commander, John Koenig retains command of the 311 men and women as their home drifts aimlessly through space encountering different alien life forms, in the hope that one day they will find a planet with a breathable atmosphere where they can finally settle. Lew Grade was suitably impressed with the story outline to give the new series a budget of £3.5 million, making it, up to then, the most expensive British television series ever made.

Gerry’s next task was to find a US actor with a suitably high profile to attract the American networks where it was vital the series succeed. The actor he decided on former I, Spy star Robert Culp. Sylvia Anderson thinks that Culp would have added an extra dimension to the series: "I wanted Robert Culp. When we met him he was quite outrageous, but he would have given the series a very interesting angle. He would not have been the stereotyped hero; he would have been scared at times, he would have made the wrong decisions." However, Gerry’s memory of meeting the star was different from that of his wife’s: “He said ‘there’s something I have to tell you. I want you to know that I’m a great actor. Something else you should know is that I’m an even better director and an even better writer.” Gerry says that at that point he decided that Robert Culp was not going to be suitable for the series.

Abe Mandell, the President of ITC in New York, had his own idea about casting. Mandell suggested the husband and wife team of Barbara Bain and Martin Landau who had been a big hit together on the US series Mission Impossible. Gerry agreed. Sylvia didn’t. “I battled very hard and stood up to Lew Grade and said 'I don't think they're right. They were okay in Mission Impossible, but having seen them, I don't think we're going to get what we should get.' But he said that they were very popular in Mission Impossible, and that they were a good commercial bet, and that was that.”

The casting wasn’t the only disagreement that the Anderson’s had behind the scenes during the creation and shooting of their latest venture and it soon became apparent that their marriage was falling apart. The first season of Space: 1999 took two years to complete and during this time tensions rose to breaking point. The break, when it finally happened was on the evening of the end of filming party. Gerry allegedly told Sylvia that he wouldn’t attend if she were going and she apparently replied, “Okay, you go.” But some time after he arrived, Sylvia turned up. According to Gerry, later that night he went home and packed his things. Their fifteen-year marriage was over.

As far as producing was concerned it was business as usual. America had received Space: 1999 very well and wanted a new series, however, Abe Mandell was insisting on a format change and also wanted to bring in an American writer. Gerry set off to the USA where he finally met Fred Freiberger, an experienced TV writer who had written and produced on the third season of Star Trek. Gerry phoned Mandell with the good news. Mandell asked if Freiberger were available. Gerry said he was. There was a pause from the other end of the phone before Mandell asked, “why is he available?”
Gerry responded: “What are you saying…you want me to hire someone who’s not available?” There was another pause before Mandell asked, “but why isn’t he working?”

In spite of Mandell’s concerns Gerry got his way and made Freiberger producer of series two, whilst Gerry himself became Executive Producer. However, Mandell was not finished. He wanted a new character introduced to the series, an young actress called Catherine Schell. This caused problems with Barbara Bain who was concerned that her role of female lead was being threatened and Gerry had to go to great lengths to keep the peace.

Abe Mandell contacted Gerry one day during the production of the second series and told Gerry that he was very disappointed that there were no monsters in the show. “In America,” he said, “monsters are all the rage and every science fiction show has to have them.” Gerry hurriedly arranged for scripts to be rewritten and called in sculptors and animatronics experts to give the show the required ‘extras’. A few months later Mandell visited the set and looked in horror at Gerry. “What are you doing, you’ve got monsters in the show?”
“Of course we have!” said Gerry pointing out that they were put there because Mandell had said US audiences wanted them.
“But that’s all changed now,” said Mandell. “Monsters are out!”

Looking back Gerry has a few regrets about the second series of Space: 1999. He would have been happier without the US interference and realises that maybe he should have retained more control himself. But he wanted to ensure an American airing for the show and realises that without their money, the second series may not have been made at all. The first series, he said, was definitely the better one.

The end of Space: 1999 signalled the end of more than one era for Gerry. It was 1976, Gerry and Sylvia Anderson were no more and neither was there any more backing from Lew Grade. Gerry’s sixteen-year association with ATV was at an end and for the first time he had to go it alone.