Andrea Riseborough
Colette McVeigh

Clive Owen
Mac

Gillian Anderson
Kate Fletcher

Aidan Gillen
Gerry

Domhnall Gleeson
Connor

Brid Brennan
Ma

David Wilmot
Kevin Mulville

Stuart Graham
Ian Gilmour

Martin McCann
Brendan

Maria Laird
Young Collette

Barry Barnes
Gerry Senior

Michael McElhatton
Liam Hughes

Gary Lydon
Geoff

Daniel Tatarsky
Watcher

Tom Bennett
Watcher #2

Nicholas Asbury
Agent

Morgan Watkins
MI5 Officer

Karl Shiels
Mulville's Driver / Gunman

Mark Huberman
RUC Officer at Hospital

Eoin Murtagh
Louie, Fletcher's Son

Nia Gwynne
Female Watcher

Alan O'Neill
RUC Officer

David Herlihy
Senior Staff Officer

Kate Nic Chonaonaigh
Henderson's Wife

Lisa Walsh
Brendan's Girlfriend

Una Carroll
Brendan's Mum

Anna Elizabeth McGrath
Mourner (uncredited)