Blake's 7, 2: The Classic Adventures, 4: Ghost Ship (Unabridged)

Description of book

Vila is scared. Of course he is. Vila is always scared.
He should feel safe. He is on board the Liberator, the most powerful ship ever constructed. He is home - but he is certainly not alone.
Ghostly figures stalk the corridors of the Liberator. Spectres who know Vila's name. Revenants. Demons.
And Vila has nowhere to run.