One of the enduring mysteries of Doctor Who is how, in 2001, Death Comes to Time made it to the air and, more to the point, did so with as solid a cast as it did. That Sylvester McCoy, Sophie Aldred, and, in a late-story cameo, Nicholas Courtney signed on for this is not surprising - all three of them, after all, have a long legacy of doing work for various fan projects and low-end Doctor Who stuff....
