Release number 145 from back in March 2011, Industrial Evolution by Eddie Robson, directed by Nicholas Briggs.
The Sixth Doctor and Evelyn Smythe take Thomas Brewster back to Victorian England, find him a job, and then hang around to see that he settles in. But there is something mysterious lurking in the cellars below the factory and it is growing in power and malevolence.
Industrial Evolution is a good steampunk story that suits the Sixth Doctor rather well. It also harks back to some of the classic adventures from the 1970s. It could almost have been written by Robert Holmes, which is high praise indeed. It's my favourite of the Thomas Brewster stories so far and it has that terrific Sixey-Smythe combination going for it as well. Strange and sad that it is the last story with either companion that we are likely to have.
One observation: The Doctor's adventures on Earth must now number in the hundreds, in all the various formats over the years. So it does rather strain credulity that stories like this one have not affected human history. Obviously this is one of the concessions we make when we suspend our disbelief, but it does make me wonder whether there is some hidden force in the Doctor Who-nverse that goes around tidying up after his exploits. Maybe that was one of the things that The Silence did while they controlled history.
Anyway a terrific story, great performances, rather good music, and a creepy, clanking creature of cogs and steam. 4 out of 5 Victorian top hats off.