Sir Horace Willoughby, a bluff rerired explorer, highly influential within the Syrtis Major colony.  Perhaps not as sharp as he once was, particularly when drunk.  Afflicted with gout.

Major Rodney Billingham, handsome Household Guards Officer sent to Mars for some unspecified offence.  Now a friend to Lord Midhurst.

Frederick "Freddie" Byrnes, a young Foreign and Colonial Officer with considerable administrative responsibilities within the Syrtis Major colony.  Freddie has shown some interest in youg Miss Pennington-Smythe.

Mrs Philippa "Pippa" Farmer, a pretty young woman, evidently bored, married to a local FCO officer.

Lady Agatha Hadbury, a free thinking young aristocrat, strikingly beautiful but shocking in her open affair with a Martian and her predilection for short cropped hair and the wearing of trousers. 

Sir Henry Amsworth, an archaeologist and retired army engineer.  An experienced explorer.

Mrs Elizabeth Amsworth, Sir Henry's wife, a formidable woman. Short, plump and highly efficient with a keen knowledge of tweed fabrics and their differing efficacies against the rigours of the African jungle.  Mrs Amsworth has formed a close bond with the much younger, but temperamentally similar, Mis Pennington-Smythe.

Kit Amsworth, the Amsworth's daughter, a sporty young thing fresh out of university and keen to establish the first Martian hockey league.  

Bob Smithson, quartermaster to the Amsworth expedition, an able man in his early 40s, efficient but not always diligent.

Major Oswald Bastable, brother to Captain James Bastable, Oswald is head of security for the Amsworth expedition.

Captain James Bastable, friend to Henry Wells, Bastable was an engineer who was last seen floating in the Martian air attached to a loose plank of driftwood, following the destruction of the Sprightly.  Certainly dead, for surely no man could have survived being lost in such a fashion among the trackless Martian desert wastes...