Between 2003 and 2008, Big Finish explored alternative realities of Doctor Who through hypothetical ‘what if?’ scenarios starring new actors as the Doctor. David Warner, Geoffrey Bayldon, David Collings, and Arabella Weir all took on the central role in the range.

The phenomenal cast also features Nicholas Courtney (Brigadier Lethbridge-Stewart), David Tennant (Colonel Brimmicombe-Wood), Bonnie Langford (Melanie Bush), Sir Derek Jacobi (Martin), Carole Ann Ford (Susan), and Terry Molloy (Davros).

A newly-repackaged collection of these eight previously-released adventures, Doctor Who – Unbound: 1-8 Collected, is now available to own for just £17.99 (digital download only), exclusively here.

Producer John Ainsworth said: “Producing the original Doctor Who Unbound series was hugely exciting, particularly as it coincided with the 40th anniversary of the TV series.

“I took it as a fantastic opportunity to not only cast new actors as the Doctor, but to explore 'what if?' moments in the Doctor Who universe by tinkering with established Who history as well as the Doctor's character and morality. I was quite trepidatious as to how they would be received, but they proved to be very popular if, in some instances, controversial.”

Executive Producer Nicholas Briggs added: “Our Unbound series of Doctor Who adventures is one of the most popular things we’ve ever done. And we receive many, regular requests from listeners to do more but it’s always tricky for us at a time when new Doctors are arriving on TV. There are, of course, the glories of our past Unbound Doctors. A fantastic collection of ‘what ifs?’ with the Doctor thoroughly and gloriously unbound by Doctor Who continuity. If you haven’t already experienced these releases, here’s your opportunity to listen to some great Doctor Who with a distinct twist.”

What if the Doctor and Susan had never left Gallifrey? What if the Doctor had not been UNIT's scientific advisor? What if the Valeyard had won? What if the Doctor had escaped the justice of the Time Lords? This collection answers these questions and more.

The eight adventures in this Doctor Who – Unbound collection are as follows:

Auld Mortality by Marc Platt

What if... the Doctor and Susan had never left Gallifrey?

In a marble mausoleum, deep in the cisterns beneath the Capitol, Gallifrey's favourite author faces his ultimate destiny.

Who is the woman who claims to be his granddaughter? Who is the sepulchral figure in robes of night? Which path should Hannibal's army take to Rome?

And on a snowy mountain high in the Alps, the Doctor remembers the ultimate question: What if he and Susan had never left Gallifrey?

Sympathy for the Devil by Jonathan Clements

What if... the Doctor had not been UNIT's scientific advisor?

1997... and a lone exile arrives on Earth, years later than planned.

On the eve of the Handover, an advanced Chinese stealth bomber crashes in the hills above Hong Kong. The discredited UNIT has just 24 hours to steal the technology, rescue the passenger and flee to international waters.

Down by the harbour, there's big trouble in Little England, a bar owned by an old soldier, who simply wants to forget the past. But an ancient evil is stirring in a place of peace.

The Doctor finds a world on the brink of terror. A world that has lived without him for years. A world that is frighteningly like our own...

Full Fathom Five by David Bishop

"If I told you the truth, I'd have to kill you...

"The Deep-sea Energy Exploration Project was apparently destroyed by dirty bombs in 2039 AD, turning the surrounding sea bed into a radioactive tomb. Rumours suggest the DEEP was conducting illegal, unethical experiments...

In 2066 the Doctor discovers the research centre remains intact. The terrible truth about what happened 27 years ago will soon be revealed. The Doctor is determined to be the first to uncover and confront the secrets of the DEEP.

But unearthing the past can have terrible consequences for your future...

He Jests at Scars by Gary Russell

What if... the Valeyard had won?

The thing about meddling with time is that one moment something is real, the next, it's been erased. Probability becomes just a possibility. Established truth becomes a theoretical falsehood. Like dominoes, as one timeline falls, the others come cascading down around it. You can engineer new timelines, new possibilities but before long, the distinction between what is, what was, what might be and what never can be becomes blurred.

Out of this grow myths, lies and legends. The Doctor was one such legend, but no one knows whether he truly ever existed. Well, not now they don't. The Mighty One, ruling the multiverses from the eternal city of Chronopolis has made sure of that.

Deadline by Robert Shearman

It's been forty years since Martin Bannister encountered the Doctor. They were different men back then. Martin was young and talented and The Times' seventh most promising writer to watch out for. The Doctor was mysterious, crotchety and possibly oriental. It was an encounter that destroyed both their lives.

Pity poor Martin now... His career is in ruins, all forgotten. His estranged wives keep dying in the wrong order, and there's a nasty green stain by the wardrobe that could be an alien footprint or, possibly, just mould.

Martin's life is about to change unexpectedly... Impromptu poetry readings. Elephant expeditions. An obligatory bug-eyed monster. And a last, desperate chance for love, before it's too late.

Sounds like it's time for the Doctor to come into Martin's life again. And sort him out. Permanently.

Exile by Nicholas Briggs

What if... the Doctor had escaped the justice of the Time Lords?

"They want to punish me for being me!"

All the Doctor has to do to avoid being caught by the Time Lords is work in a supermarket and go to the pub. It's a cunning plan -certainly far less dangerous than fighting the dreaded Quarks and all those other alien fiends.

But just when everything seemed mundane and safe, alien transmissions, exploding poison gas, Princess Anne and wobbly trolleys burst onto the scene to ruin everything. It's a crisis! A fiendish alien plot! And the Doctor must use all the resources at her disposal to defeat it.

She'll probably need to have a large vodka first, though.

A Storm of Angels by Marc Platt

What if... the Doctor really had changed History, even just the tiniest bit?

1480: Leonardo da Vinci visits the stars.

1508: Vasco da Gama sets foot on Mars.

1585: Francis Drake begins charting the Asteroid Belt.

1588: Earth is destroyed by a storm of angels.

The Doctor was really enjoying his freedom. But now there’s a Temporal Agent on his tail. Gloriana and the President of Gallifrey are not amused. And Susan’s none too well either.

Possibilities, like the Doctor, have a habit of running away with themselves. But who cares, when the jewels are so dazzling...

Masters of War by Eddie Robson

The Doctor and his travelling companion, retired army officer Alistair Lethbridge-Stewart, take a random trip in the TARDIS and land on the planet Skaro.

The Doctor helped the Thals to defeat the Daleks years ago, so he is surprised to find the Thal city under Dalek occupation. He determines to help them again, but what is the Daleks' purpose in keeping the Thals alive?

Does it have anything to do with the Daleks' mythical creator, named in their teachings as Davros?