Isn't he the voiceover artist of Jack FM (or was?)
Yep, he was, and his voiceovers were one of the best things about Jack FM in the UK. He was the second best thing in Blake's 7 behind Servalan. A great actor, and will be much missed.
Apparently it was Paul Darrow's wish that he'd still be the voice of Jack after he died. OXIS Media who own Jack FM haven't made a decision whether to stop using his voice, but at the moment he's still the voice on Oxfordshire's Jack, Union Jack, Jack 2 and Jack 3. He isn't the voice of Jack Radio, the female skewed music station.
I can't see them needing to make a decision until they need to do a new session to record additional material, that is when they will have to decide whether to do an E4 and get a soundalike (Peter Dickson doing an impression of Patrick Allen) or to redo the whole lot with a new voice.
Or if they can find a clever way to mix and match, such as introducing a second station voice and using a bit of both on each jingle, eg Paul Darrow's existing recordings for the station name, new voice for the feature name or strapline etc. That would give a nice way to move forward while still respecting his wish.