This second series was dramatised by a very different writer from the first. Where Alick Rowe had been interested in people and their individual quirks, Christopher Penfold was far more of a conceptual writer, and with a stronger interest in making use of the science fiction genre:

I like science fiction that extrapolates from Earth situations in such a way that allows us to understand our Earthly experience by looking back from outside. The driving force of my interest in the genre is it enables us to ask questions about where we are going now.

Asking these questions, he weaves in ideas of information networks, bio-engineering in which computers are joined to organic tissue, cultural imperialism. It would be wrong to see him as purely a hard-SF enthusiast, though: his one-time writing partner on Space:1999, Johnny Byrne, has described him as a moralist. The son of a vicar, Penfold is greatly concerned with good and evil.

Penfold faced a formidable challenge. He was taking up somebody else's established programme format, yet without having seen the actual episodes. He was aware that the producer would have preferred a different writer (Alick Rowe, who was not available) and that he would be writing series two alone. But above all he had to adapt an impossible book, whose drama is intensely psychological. Outwardly, not much happens. The main action is delayed until the midpoint, after which only three characters actually speak, one of those an alien. The Masters cannot have expressive faces and the humans have to wear breathing masks almost all the time, which is almost as bad. Not a single character in the entire book is female, unless you count Eloise, who is dead. The City is horrific and its most forbidding aspect, the higher gravity which is the "Lead" of the title, cannot possibly be realised on television. Penfold has been criticised for deviating from the book but he could hardly have avoided this.

In the less problematic "journey" parts of the book, Penfold did adhere to the original. So much so that the Tunnel, the refuge of the free men, is moved quietly back to its authentic location (the Jungfrau, not the Mont Blanc massif as claimed in series 1). We are told that the City is near Koblenz and that the barge travels there from Basel, which can be deduced from the text of the book but is never openly stated. Will's cover identity, "Willi Sachs", is as an athlete from Partenkirchen, in the Tirol, the west-Austrian Alps (now a major ski-resort, Partenkirchen is actually a few miles over the border into Germany). On their return to the White Mountains, the travellers pass through Geneva and then due east, up the valley.

Many viewers liked Penfold's scripts, as preserving an upbeat action-series story and delivering on the science fiction elements which the City promises. In most of the critical books on television of the period, series 2 is praised as a great improvement on series 1. For myself, I am less persuaded of this, not least because of the dialogue, which at its worst points are painfully unspeakable. (Will to Master 468: "I honour you above all beings"; Zerlina to Papagena: "Make the most of it, girl", and a lot more girl talk like that. And why exactly are they named after Mozart operatic heroines? Because it was what happened to be playing on Penfold's hi-fi when he was writing the script?) Will is just a little too stupid at times, which can be convenient for the plot but is out of character: he almost seems to go out of his way to give himself away at times. Similarly, Penfold doesn't handle the need to keep reminding the audience of the plot very adroitly. Why do Will and Beanpole tell the circus troupe about the approach of the Masters' spaceship? This is absurd. Lastly, I find Penfold a somewhat self-conscious writer: he gives florid speeches to three minor characters (Shankar, the second Pierre and the Cognosc) which question the whole basis of the plot, accusing it of naivety. It was no doubt intended to be subtle and thoughtful but the result is odd and clumsy.

Considering Penfold's great experience, and that he went on to be script editor of the police-soap The Bill, it's odd that his dialogue can be so variable. But these are only occasional irritations in the end, and most of the writing is sound enough: the first episode of the second series is an excellent montage of visuals and words, portraying a community and reminding the viewers of the basic idea of the show with great narrative economy, much as the first episode of the first season had done. Arguably it's the best episode in either series; it must have been horribly expensive to make.

Whereas the first series had stretched out the action of the book to about 8 episodes, then adding 5 more of new material, the second series stretches its book out to 10 episodes and adds 2. Nevertheless it feels far more distant from John Christopher's original. One obvious reason is that, whereas Alick Rowe omitted almost nothing from The White Mountains (except a few scenes in Wherton), Penfold deletes all of chapters 3 and 4 of The City of Gold and Lead, in which our heroes journey down-river by raft and are stranded on an island. Perhaps Chapter 3's rafting would have been difficult to realise on screen (think of the location filming problems, the safety angle, the difficulty of getting the raft actually to work...). It's a pity, though. Chapter 4, the story of an island hermit, is the most unpleasant moment in any of the books, and sits rather unhappily in them; one can see what John Christopher was getting at, in making his heroes do something awful from necessity, but it doesn't quite join to the rest of the plot. It's easy to see why this was dropped from the television version and easy too to see why Penfold wanted to fill the gap with some female characters. What he ended up with was an inconsequential farce (episode 3), entertaining up to a point but fundamentally pointless, dropping the narrative at a crucial time -- when the viewers, promised infiltration of an alien city in episode 1, have still not sighted the battlements.

Many of Penfold's additions were similarly distant from the mood of the book -- the presence of the Pink Parrot disco-bar in the City is a case in point, as is the circus, though if you look hard enough in Christopher's writing you can find justification at a pinch. (Henry mentions having seen a circus in The White Mountains.) Penfold also removes a number of unpleasantries from the original story. In his version, Henry is kept back in the White Mountains because he's too useful, not because he isn't a good enough runner. Ulf is a good man with a problem, not a drunkard dying of tuberculosis. Will and Beanpole don't steal the crippled hermit's only boat. Beanpole doesn't fail through lack of courage, but because he has blamelessly twisted his ankle. Fritz's health does not steadily dwindle. The City doesn't really seem so very unpleasant. Eloise is not dead but only in suspended animation. And so forth. At least some of these changes of mood are inevitable in a television version which could be broadcast at a reasonably early hour of the evening, particularly at a time when the BBC's other sci-fi show, Doctor Who, was under not infrequent attack in the press as "too violent". But the grinding terribleness of the book's version of the City is somehow lost. Interviewed recently, John Christopher said some of the later parts of the second series had "got so far off my path that I just couldn't recognise it... all that circus stuff."

On the other hand, one of Penfold's two substantial inventions, the human-tended power station, is very successful and keeps an interesting sub-plot moving tidily along. Better, it gives Fritz a chance to become a major character in his own right. It's perhaps worth noting that the six episodes within the City are the only ones in either series of the programme in which the narrative divides to follow two lines: Will's activities and Fritz's, which only overlap once or twice per episode. Cross-cuts between the two allow the video editors to construct a tense story-line. Penfold himself thought these episodes the best:

I was most pleased in the second series with those episodes directed by Bob Blagden -- the ones inside the Tripod city. They were thinking science fiction.

Penfold's big thought is the Cognosc. In fact, this is an old preoccupation of his, as can be seen from his Space:1999 episode Space Brain, a classic example of how dreadful special effects can wreck intelligent sci-fi: at the end Moonbase Alpha fills up with detergent foam against a soundtrack of Mars, the Bringer of War. Said Penfold:

The idea of the heavenly bodies as being macro brain cells is one that appealed to me and still does. What was achieved on the set with foam wasn't quite in line with that!

The Cognosc is tied up with a new back-story for the trilogy: we are told that Man lost dominion over the Earth as a result of a nuclear war, after which the space culture felt obliged to move in and take over. (This is a motif altogether absent in the novels, and indeed contradicted by the (later) prequel.) There is some talk of "space imperialism" suggestive of the Reagan policy towards Latin America, dating the production somewhat to the 1980s.

Finally, a note on what Penfold doesn't include. We never quite see the characters exploring forbidden regions of the City, such as the planetarium or the Stadium of the books. There is just a little too much Doctor Who-esque running about in corridors instead, even if the interleaving model shots are superb. Will and Fritz are not quite overwhelmed enough by the strangeness and horror of the place, so that this isn't quite communicated to the viewer. But the City episodes remain remarkable by BBC sci-fi standards: a cut above any production standards seen before, or since.