Sectarian violence in Northern Ireland cast a long shadow over the country for more than 30 years.

The cycle of bloodletting largely ceased with the signing of the 1998 Good Friday Agreement but deep emotional scars remain, providing film-makers with stories drawn from fact and fiction to recreate these dark decades of murder, reprisals and political meddling.

In the mid 1990s, journalist Tom Bradby worked as ITN’s Ireland correspondent and reported on momentous events including the peace process and IRA ceasefire.

Soon after, he penned his first novel, Shadow Dancer, a taut thriller set against the backdrop of the brutality he had witnessed firsthand.

This suspenseful yarn, about a young woman’s betrayal of the people she holds most dear, translates elegantly from the page to the screen under the aegis of Academy Award-winning director James Marsh (Man On Wire).

Twenty-something single mother Colette McVeigh (Andrea Riseborough) has never forgiven herself for inadvertently sending her young brother to his death in 1970s Belfast.

She harbours a deep resentment for British forces, which fired the fateful bullet, and has assuaged her guilt by becoming an active member of the IRA alongside her two brothers, Gerry (Aidan Gillen) and Connor (Domhnall Gleeson).

British police apprehend her during an attempted bombing of the London Underground and MI5 operative Mac (Clive Owen) leads the interrogation.

He provides evidence that an IRA bullet killed her brother all those years ago then offers Colette an ultimatum: act as a mole, secretly feeding back vital intelligence on terrorist plots, or serve 25 years behind bars and forego precious time with her young son Mark (Cathal Maguire) and mother (Brid Brennan).

Reluctantly, Colette agrees to work for MI5 and she provides Mac with details about an assassination attempt spearheaded by Gerry and Connor. British Security Forces ambush the IRA, exposing the existence of an informant at the heart of the IRA.

Marsh directs with cool detachment, never passing judgment on his characters as they make the best of the dire hands that fate has dealt them.