Thomasin McKenzie

Rose

Ben Radcliffe

Eric

Katherine Waterston

Lady Davenport

Emma Laird

Poppy

Tom Goodman-Hill

Inspector Watt

Ramon Tikaram

Darvesh Khalid

Tim McMullan

Cyril

Anna Maxwell Martin

Mrs McAllister

Sue Johnston

Great Aunt Bonaparte

Tom Felton

Archibald

Damian Lewis

Lord Davenport

Hayley Mills

Rose Davenport (voice)

Adam Woodward

Bert Chester

Lily Knight

Fifi Valentine

Erin Austen

Mary & Constance Bechdel

Lizzie Hopley

Phyllis Davenport

Jason Done

JRR Tolkien

Laurie Ogden

Patricia

Paula Wharton

Mrs Kitchen

Nathan McMullen

Alexander

James Stanley

Richard

Karen Henthorn

Sister Jude

Ian Bartholomew

Austin Blaine

Nicholas Hale

Banker

Lee Boardman

Karl

Charlie Rawes

Drunk Alan / Prison Guard

Shaun Mason

Army Officer

John Thomson

Bill

Jimmy Carr

Vicar

Gemma Wardle

Gladys

Dean Fagan

Prison Guard

Brainard Oyani

Prospective Hall Boy

Magdalena Sverlander

Rose Seller

Alex Butler

Lionel (uncredited)

Nathan Hall

Footman (uncredited)