Dev Patel
Srinivasa Ramanujan
Jeremy Irons
G. H. Hardy
Toby Jones
Littlewood
Devika Bhise
Janaki
Stephen Fry
Sir Francis Spring
Kevin McNally
Major MacMahon
Jeremy Northam
Bertrand Russell
Anthony Calf
Howard
Pádraic Delaney
Beglan
Shazad Latif
Chandra Mahalanobis
Roger Narayan
Scribe
Arundathi Nag
Komalatammal
Dhritiman Chatterjee
Narayana Iyer
Richard Johnson
Vice Master Henry Jackson
Raghuvir Joshi
Narasimha
Malcolm Sinclair
Professor Cartwright
San Shella
Dr. Muthu
Richard Cunningham
Hobson
Thomas Bewley
Baker
Pip Barclay
Student
David Shaw-Parker
Porter
Dominic Cazenove
Waiter
Nicholas Agnew
Andrew Hartley
Alan Booty
Grocer
Shenagh Govan
Postal Worker
Alexander Forsyth
Cadet
Enzo Cilenti
Doctor
Elaine Caulfield
Hospital Nurse
Alex Bartram
Hospital Doctor
Christopher Ravenscroft
J. J. Thompson
Imogen Sage
Nursie (uncredited)