Srinivasa Ramanujan

Dev Patel

G. H. Hardy

Jeremy Irons

Janaki

Devika Bhise

Howard

Anthony Calf

Littlewood

Toby Jones

Stretcher Bearer

Alexander Cooper

Major McMahon

Kevin R. McNally

Chandra Mahalanobis

Shazad Latif

Bertrand Russell

Jeremy Northam

Sir Francis Spring

Stephen Fry

Beglan

Padraic Delaney

Komalatammal

Arundathi Nag

Roman Green

Vice Master Henry Jackson

Richard Johnson

Andrew Hartley

Nicholas Agnew

Narasimha

Raghuvir Joshi

Ward Sister

Eleanor Inglis

Narayana Iyer

Dhritiman Chaterji

Mr. Iyengar/The Scribe

Roger Narayan

Hobson

Richard Cunningham

Alan Bentley

Patient

Arthur Wilde

Student/Cadet

Devlin Lloyd

Fellow of the Royal Society

Pat Carney

Professor Cartwright

Malcolm Sinclair

Waiter

Dominic Cazenove

Dr. Muthu

San Shella

Porter

David Shaw Parker

Baker

Thomas Bewley

Postal Worker

Shenagh Govan

Fellow

James Thomas Scott

Student

Pip Barclay

Hospital Doctor

Alex Bartram

Nursie (uncredited)

Imogen Sage

Grocer

Alan Booty

Barnie

Alexander Forsyth

Wounded Soldier

Jon Lawes

Student Bully/Soldier

Jack Philips

Doctor

Enzo Cilenti

Hospital Nurse

Elaine Caulfield

J. J. Thompson

Christopher Ravenscroft