Meet the cast of Decline and Fall

Who does he play? Solomon Philbrick is the butler at Llanabba, because obviously every school needs a butler. He's a bit of a shady character with a terrifying streak, and poor Pennyfeather isn't sure what to make of him. Jack Whitehall says: "I loved doing scenes with Stephen Graham, he is very scary and I think revels in how terrifying he can be. He's a very physical performer; he liked punching me and slapping me and didn’t ever tell me that he was going to do it in the scene."

Where have I seen him before? Stephen Graham got his big break as dim-witted Tommy in the Guy Ritchie film Snatch (2000), having gone along to the audition with his friend. Since then he's played Atticus in Taboo, Inspector Heat in The Secret Agent, Combo in This Is England 90 and 86, Al Capone in Boardwalk Empire, Vincent Macmaster in Parade's End, Corporal Danny Peterson in Occupation and was the star of The Watchman.

Vincent Franklin – Mr Prendergast

Who does he play? Prendergast doesn't enjoy his time at the school any more than Captain Grimes. A former clergyman who has disastrously lost his faith and had to quit the cloth, he is beaten down and demoralised. Worse, he knows he commands absolutely zero respect from his students – partly because of his terrible toupé. He's very happy to join Grimes for a drink.

Where have I seen him before? Vincent Franklin has an impressive comedy pedigree, with a CV that includes roles in Cucumber, Banana, The Thick of It and Twenty Twelve. He played Andy Shepherd in Happy Valley and Chris Parson in Doc Martin.

Gemma Whelan – Diane (Dingy) Fagan

Who does she play? Dingy Fagan is the daughter of Llanabba's headmaster. She is used to getting things done, she's no-nonsense, and is considered to have a masculine streak.

Where have I seen her before? Gemma Whelan is best known as Yara Greyjoy in Game of Thrones, one of the longer-surviving characters in the brutal fantasy series, and was last seen as the mother of abducted schoolgirl Shannon Matthews in Moorside. But she also has a funny side, performing stand-up as her character Chastity Butterworth.

Katy Wix – Florence (Flossie) Fagan

Who does she play? Flossie is Dr Fagan's least favourite daughter. Bullied by her father, dismissed by Dingy, she really has it hard at Llanabba.

Where have I seen her before? Katy Wix is best known for playing Fergie in The Windsors and Daisy in Not Going Out. She has also appeared in Miranda, and played Nurse Cornish in an episode of Sherlock.