In Bessie Come Home, Paul Magrs showed us what ultimately happened to the Third Doctor’s daffodil-yellow roadster Bessie in the years after she helped the stranded Time Lord save the Earth time after time after time. In London, 1965, he showed us what happened when the First Doctor’s first Earthling companions, Ian Chesterton and Barbara Wright got home to London two years out of their time.

In Sleeper Agents, he makes the next logical leap. For those unfamiliar with the First and Second Doctor, after Ian and Barbara, the First Doctor had a handful of other companions – Vicki, Steven, Dodo – and then something happened that hadn’t happened before.

In The War Machines, the First Doctor returned to Earth in a time that corresponded to his viewers’ reality – 1966. While Dodo more or less wanders off in the middle of that story without saying goodbye, the Doctor is entirely unperturbed, doesn’t make any further efforts to collect her, but does take two new travelling companions with him – Polly Wright (yes, just like Barbara. No, as far as we know, no relation) and Able Seaman Ben Jackson (played by Anneke Wills and Michael Craze respectively).

They see him through his very first regeneration (at least, as far as anyone was aware until the Thirteenth Doctor’s explosive Timeless Children storyline) at the end of a battle with the Cybermen, and they stay with him in his second incarnation until an alien plot at Gatwick Airport almost miraculously sees them returned to London on the very day they originally left.

Opting to stay behind and pick up their lives on Earth while the Second Doctor and their travelling companion Jamie get involved in a cunning Dalek plot, that’s the last we ever hear of them in the TV show. There was a sense that, just as was the case with Ian and Barbara before them, the two might begin a closer relationship once they left the Tardis and settled back into their lives, but no-one has ever had the scope to tell the story of what really happened to them when they left the Doctor behind.

Until now.

Now, Paul Magrs takes us back to that day in July, 1966. Sleeper Agents takes all the assumptions and realities of coming back to Earth and embroiders us a real world setting that pits Polly and Ben against a growing threat of Earthbound espionage, first mentioned in Bessie Come Home, and significantly enlarged in London, 1965.

With Anneke Wills reading the story, that day in July becomes probably the most story-rich day of all time in Doctor Who history. It has the defeat of WOTAN and its war machines at the Post Office Tower, the plane-based plotting of the Chameleons at Gatwick, the time-travelling chicanery of the Daleks in Evil of the Daleks, and now, the espionage antics of the mysterious Mr Harmer and Miss Leamann, messing with the lives of Ben and Polly on their return.

Harmer and Leamann have featured in both of Paul Magrs’ previous Beyond The Doctor stories, and we’ve learned more about them on each occasion. Here, they insinuate their way into both the companions’ lives, just as they did into Ian and Barbara’s in London, 1965. But whereas that was a gradual, insistence pulse of a presence over quite a space of time, here they’re nothing like so subtle, and they spring their pre-prepared traps within a day of Ben and Polly arriving back.

There are other connections, too. On returning to her work at the Post Office Tower, Polly finds herself set to tying up stories for Penumbra, a science fiction magazine run by Mr Harmer – as featured in London, 1965, where it includes the stories of one Ian Chesterton. And just as in London, 1965, Paul Magrs takes a long way round the somewhat expected relationship potential of Ian and Barbara, involving them in fights and a gradual distancing rather than some immediate fan-fiction festival of I Love Yous, so in Sleeper Agents, he explodes – at least for the immediate future – the idea that Ben and Polly will simply fall into a relationship, united against the world by their adventures in time and space.

The difference between the two potential couples is that here, the tension between them is foregrounded fast, with Ben coming out and saying that he’d assumed that picking up their lives on Earth would include picking up with each other. That leads to them speaking aloud a reality that hadn’t mattered since they both stepped on board the Tardis – Polly is a posh young woman, with a Chelsea flat and a job at a spanking new London landmark, whereas Ben is “just” an Able Seaman in the Royal Navy, not an officer, not an admiral. Now that they’re back on Earth, he immediately feels the disparity of their upbringings and expectations, in a way he hadn’t while they were equalised by the life of time travellers.

It’s a brave note of social realism from Magrs that effectively helps land the listener back in the ‘real world’ of 1966 London with a bump of disappointment. Time and space are over now, and Ben and Polly have just their own resources to help them through whatever will come next.

That becomes a distinct issue when Ben is summoned to Whitehall for top-level debriefings, and Polly comes increasingly under the persuasive thumb of her new boss, Mr Harmer.

And then there are the white cats. Seemingly everywhere, they’re followed by people accompanied by white cats – James Bond style. That’s a sinister note underlined by the introduction to our lives of Polly’s own monochrome moggy, the distinctly blandly-named “Mr Puss.”

When the traps are sprung, we learn a lot more again about Harmer and Leamann, and why they’re particularly interested in acquiring friends of the Doctor and draining the secrets of time, space, the Tardis, and all the cool things it has let the time travellers experience.

Then we’re into some serious Tracy Island territory, with a good deal of Sixties Avengers tone, too – spies, interrogations, secret hidden bases in places there absolutely shouldn’t be secret hidden bases. But there’s more insidious work afoot, too.

The idea of brainwashing the friends of the Doctor to become the sleeper agents of the title feels like something secondary, on top of the benefits of all the information they hold locked in their brains, but that’s where we go with this story.

It also feels like the ultimate, horrifying betrayal of both the people the Doctor chooses to have travel with him, and of his own moral codes, to have his friends coldly repurposed as potential sleeper assassins.

And while the ending is technically happy, with Ben and Polly seeming to escape from the clutches of Leamann and Harmer, there’s an understandable element of worry there too, as Polly articulates. Yes, they’ve escaped, but was it too easy? Was it a reality constructed to play into their experiences with the Doctor – they run down corridors, do something clever, disable some futuristic androids, and make it out of the hidden base in the nick of time.

Like they always do.

But can either of them trust, any more, that what they think happened is what really happened? Or have they simply forgotten what really happened? Will they one day wake up and decide to go to a place with a weapon in their hand, to do the unremembered bidding of the evil Harmer and Leamann?

It’s a quivering, terrifying uncertainty at the end, and it also plays into another fear that Polly, who is our leading point-of-view character here, expresses.

What about the others?

During their fight for freedom, both Ben and Polly are convinced the other is being successfully brainwashed. What if they both were? And, importantly, what about the other friends of the Doctor?

While trying to escape, they discover a fake version of the Tardis console – as constructed in London, 1965 based on the memories of Ian Chesterton and Barbara Wright. What other friends of the Doctor have visited the secret base? We know there are some – Miss Leamann is unable to stop herself revealing that much. What about Dodo, who simply wandered off before the war machines got down to their city-conquering business? Who else might there be, out there, ready to pull a random trigger, or ready to share the secrets of the Doctor’s machine as far as they understand them?

As with London, 1965, Paul Magrs goes down the road of Sixties-style TV adventure, rather than overly focusing on the potential relationship dynamics of the two companions who might (and indeed in Ben’s case, absolutely does) consider that a return home would be the start of a deeper relationship.

But whereas in London, 1965, the ending tends towards positivity, here, things are much less certain, much more circumspect and worrying as the story reaches its conclusion. Where, and whom, will Harmer and Leamann strike next – and what damage have they already done?

Sleeper Agents is a must-listen if you want to know what happened to Ben and Polly next – and there’s hardly a Who-fan on the planet that could resist finding out. What it delivers is a strong dose of social realism, followed by a cracking Sixties-style adventure plot that ends with a good solid shiver down the spine, and a need to get the next instalment, The Penumbra Affair, when it’s released in May 2022. Tony Fyler