Howard Attfield
From Tardis Wiki, the free Doctor Who reference
Howard Attfield (1947-31 October 2007) played Geoff Noble in DW: The Runaway Bride. He was signed to reprise the role during Series 4, but died early into production of the season after filming several scenes for DW: Partners in Crime.
As a result, his completed scenes were refilmed with Bernard Cribbins playing a different character, Wilfred Mott, though the footage was later included on the DVD release of Series 4. A line of dialogue referencing Geoff Noble in DW: The End of Time, Part Two was included as a tribute to Attfield.