Philip Martin wrote two Doctor Who serials in the 80's, Vengeance on Varos (1985) and Mindwarp (1986).
Lost story Edit
He also wrote a story for The Lost Season called Mission to Magnus which featured the return of Sil from Vengeance on Varos. It was never filmed after the show was put on hiatus in 1985.
A novelised version was released by Target in 1990 and a Big Finish ear story based on the serial was released in 2009.
He also, rather lamentably, "wrote" The Creed of the Kromon, Big Finish's worst audio ever. Yes, worse even than that one.