1917 (15) Four stars

Practice makes breathlessly choreographed and nail-bitingly tense perfection in Sam Mendes's real-time thriller, inspired by stories of The Great War told by the director's grandfather, who served as a lance corporal.

Shot in real-time in several exquisitely staged single takes, which have been seamlessly stitched together by editor Lee Smith into a continuous fluid shot, 1917 is the product of six months of intense rehearsals and preparation, which included a physically gruelling training camp for hundreds of actors including leads Dean-Charles Chapman and George MacKay.

They undertook daily military drills in hobnail boots, acclimatising to the weight of uniforms and weapons before filming began so it would become second nature to check bayonets as hell unfolded around them.

This pre-production period allowed Mendes to work closely with Oscar-winning cinematographer Roger Deakins to meticulously map out the intricate camerawork of each sequence, which places us in the trenches with the characters or pirouettes around impossibly tight spaces as bullets scythe through the air and blood seeps into shifting seas of thick mud.

It's a tour-de-force of technical daring, which repeatedly dazzles and dumbfounds, juxtaposing heart-breaking brutality and self-sacrifice with moments of dreamy, poetic introspection.

Mendes's script, co-written by Krysty Wilson-Cairns, oscillates between agonising suspense (a sprint across No Man's Land littered with the corpses of fallen horses towards the German trenches) and ominous calm (a short journey in the back of a truck crammed with troops).

This is visceral, gut-wrenching film-making that marches us into battle in uncomfortable proximity to the characters, compelling us to hold our breaths for long stretches of the two hours.

Lance Corporal Tom Blake (Chapman) and Lance Corporal William Schofield (MacKay) begin April 6, 1917 in peaceful slumber against a tree as thunder rumbles in the distance.

The men are roused to receive orders from General Erinmore (Colin Firth), who must prevent Colonel Mackenzie (Benedict Cumberbatch) from leading The 2nd Devons into a trap set by the Germans.

"We would lose two battalions - 1,600 men - your brother among them," Mackenzie sombrely informs Blake.

The Germans have severed all telephone lines so the only way to warn The 2nd Devons is to dispatch Blake and Schofield on foot into enemy territory to reach Mackenzie before dawn, when the fateful order will be given to attack the line.

1917 unfolds in real-time, pushing actors to the physical limit as we plunge headfirst through the emotional wringer with them, experiencing similar dizzying gut-punches as tragedy stalks their odyssey.

Thomas Newman's orchestral score possesses the urgency of a ticking pocket watch, underscoring Mendes's directorial brio and devastating performances from Chapman and MacKay.

Fleeting cameos from the likes of Andrew Scott, Mark Strong and Richard Madden don't distract from an intimate tale of valour and brotherhood under fire that sears into the memory.

SEBERG (15) Two stars

Starting in the late 1960s, the FBI's counterintelligence programme under President Nixon and FBI director J Edgar Hoover targeted Iowa-born actress Jean Seberg for her involvement with the Black Panthers.

Documents show that the FBI planted false rumours in newspaper gossip columns to suggest that Seberg's pregnancy was the result of infidelity with a black lover.

A distraught Seberg subsequently took an overdose of sleeping pills.

She survived the suicide attempt but her daughter, delivered prematurely, died two days after birth.

The FBI's persecution of Seberg, who became an icon of the French New Wave when she starred in Jean-Luc Godard's 1960 picture Breathless, should be rich pickings for filmmakers.

Sadly, director Benedict Andrews fails to hit the mother lode in his opaque drama, which speculates about Seberg's emotional turmoil in the most simplistic terms.

Kristen Stewart is luminous in her portrayal of Seberg but she's repeatedly short-changed by screenwriters Joe Shrapnel and Anna Waterhouse, who distil each cruel turn of events in expository dialogue like when her lover summarises: "There's a war against black people in America. You just got caught in the crossfire."

In May 1968, Jean Seberg (Stewart) leaves Paris, her screenwriter husband Romain Gary (Yvan Attal) and young son Diego (Gabriel Sky) to travel to Los Angeles to audition for the role of Elizabeth in Paint Your Wagon.

She's indifferent to the role - "It's a western musical. It's irrelevant. I want to make a difference!" - but hard-nosed agent Walt Breckman (Stephen Root) knows it's a savvy move for Jean's career.

Their flight is interrupted by outspoken black civil right activist Hakim Jamal (Anthony Mackie), who argues that Malcolm X's widow should be given a seat in first class.

His impassioned rhetoric impresses Jean, who raises a fist in solidarity with the Black Panthers on the airport runway as photographers swarm.

Soon after, Jean becomes romantically entangled with Hakim, who has a wife (Zazie Beetz), which brings her to the attention of the FBI.

Los Angeles division chief Frank Ellroy (Colm Meaney) intends to exploit Seberg's sympathy for Hakim to gain valuable intelligence on the Black Panthers.

FBI agent Jack Solomon (Jack O'Connell) and partner Carl Kowalski (Vince Vaughn) are tasked with closely monitoring Seberg.

Their interference has a profound effect on the actress' mental well-being and she slides inexorably towards self-destruction.

Seberg feels like a missed opportunity considering the calibre of talent in front of the camera.

Stewart lays herself physically bare more convincingly that she is able to expose her character's psychological fragility, while O'Connell's conflicted FBI agent embodies the frustration we feel about words left unsaid.

The disjointed narrative is counterbalanced by eye-catching period details.

UNCUT GEMS (15) Four stars

Adam Sandler turns in the best performance of his career in Josh and Benny Safdie's thriller set on the streets of 2012 New York City.

Wheeler-dealer jeweller Howard Ratner (Sandler) has torn apart his family by moving in with mistress and lover Julia (Julia Fox).

His emotionally bruised wife Dinah (Idina Menzel) is poised to divorce him after Passover while she cares for their three children, Marcel (Noa Fisher), Eddie (Jonathan Aranbayev) and Beni (Jacob Igielski).

Business is tough for Howard, who is heavily debted to loan shark Arno (Eric Bogosian).

The jeweller hopes to turn around his fortunes by submitting a black opal for auction, which he believes should be valued at one million dollars.

Boston Celtics basketball player Kevin Garnett (playing himself) becomes obsessed with the black opal, believing that the uncut gem brings him good luck on the court.

Howard reluctantly allows the athlete to take temporary ownership of the opal then bets heavily on a Celtics victory.

Surely, his luck has to change...

FILM CHART

1. Star Wars Episode IX: The Rise Of Skywalker

2. Jumanji: The Next Level

3. Little Women

4. The Gentlemen

5. Andre Rieu; 70 Years Young

6. Frozen II

7. Jojo Rabbit

8. Spies In Disguise

9. Cats

10. Playing With Fire

(Chart courtesy of Cineworld)