Doctor Who: The Doctor's Regeneration Episodes Ranked Worst To Best

What is canon? How do you define canon? Specifically, is Big Finish officially Doctor Who canon? Well, the following tweet from Nicholas Briggs should settle this, rather irrelevant, debate: "No argument. When we launched in 1999, the BBC issued a statement saying we were the official continuation of Doctor Who stories. So there."

Briggs, himself, writes this final part to what is a terrific audio anthology - The Sixth Doctor: The Last Adventure, which is connected in much the same way as the Tenth Doctor's "he will knock four times" story arc from the 2008-2010 specials. He creates a dynamic and dramatic plot that's complex enough without dulling it with too much exposition.

The beauty of an audio drama is that you can get yourself lost in the awesome and imaginative ideas in this script. Things like: the Valeyard being created by the black ops weapons department of the Time Lords, and the Valeyard engineering himself to become Rassilon - now that would be an amazing spin-off.

Colin Baker and Michael Jayston's verbal game of one-upmanship is a delight to the ears. The Doctor and Genesta bounce off each other so well that you wonder whether he may use her Yorkshire accent in a future incarnation.

The spectral sounds of a foreboding score combined with the terrifying Gelth-like Nathemus and Jayston's marvellously Machiavellian laugh, make it the most menacing countdown clock for the Sixth Doctor's final six minutes. But just in the nick of time, he has the last laugh.

Goodbye redeemed Doctor. Hello safe hands: that disparaging theory about Six hitting his head on the TARDIS console is dispelled in this lovingly-crafted live action edit.