A novel featuring the Third Doctor, Jo Grant, UNIT and Magrs' own invention, Iris Wildthyme, a renegade Time Lady whose Tardis is shaped like a double decker bus and who claims to be the Doctor's on-off girlfriend. Magrs recycled a lot of the jokes and some of the plot from this book for the Big Finish audio Excelis Dawn, with Iris (as per usual) played by Katy Manning. But Verdigris is an amusing sideways look at the Third Doctor era, with the bad guys in one scene trying to convince Jo that it is all a cruel hoax: "Think about every alen artifact or creature you have ever seen. Weren't they always surrounded by a nimbus of blue light? Didn't they sometimes look a little ... unconvincing?" And Mike Yates gets reduced to a two-dimensional cardboard cutout, so not much change there then. It's not terribly substantial, with some promising elements (eg Iris' companion, Tommy) left unexplored, but quite good fun.
(I've also been listening to The Magician's Oath from Big Finish, also set in this period; Verdigris is better.)