Although a remake of Chinese film ‘Internal Affairs’ this film feels fresh and original in its Boston setting and covering the criminal network of Irish-American mob boss Frank Costello (Jack Nicholson).

We see two cadets graduate who become two very different cops. Both work for the S.I.U (Special Investigation Unit) under the control of Detective Captain Queenan (Martin Sheen) and Detective Sergeant Dignam (Mark Wahlberg). At their respective interviews with their superiors we learn that Colin Sullivan (Matt Damon) is an ultra confident, clean cut, charming young man who is in fact a mole for Costello. On the other side of the spectrum we have William Costigan (Leonardo DiCaprio) who although a model student and police officer has a family background that includes plenty of hoods and crooks, ideal then for him to become a mole for the police and infiltrate Costello’s criminal organisation. So we have a nice juxtaposition where all is not as it first appears.

The film moves at a comfortable assured pace and there is plenty of banter between cops and hoods as the scenes jump back and forth. For example Sergeant Dignam says in one police briefing ‘my theory on feds is you treat them like mushrooms, feed them s**t and keep them in the dark.’ The characters are well fleshed out and the world they inhabit is realistic and bleakly vivid.

Sullivan manages to charm the S.I.U.’s Guidance Counsellor Madolyn (Vera Farmiga) and the two date, this is intercut with poor Costigan mixing with some terrifying hoods as he infiltrates Costello’s organisation.

Jack Nicholson is at his best here portraying Costello as a charming but also unpredictable and ruthless sociopath. He rules his empire through fear and intimidation and literally does not care what he does or says. His scenes are both at times comic and disturbing.

As the surveillance continues we see the bureaucracy of the police force with its many departments unclear of what each other does. We also see the strain playing on Costigan as he suffers with panic attacks and insomnia. He too meets Madolyn in a professional capacity that nicely contrasts with Sullivan’s meetings with her as Costigan is literally cracking up by keeping in character undercover.

All the while Costigan is suffering we see the smug Sullivan assisting his boss stay one step ahead of the police at all times by virtue of his insider knowledge. The film cleverly crafts the suspense and tension as the two sides feint and probe like champion chess masters. Suspicion and uncertainty abound and there is paranoia in both camps.

The true revelation here is DiCaprio. He has always been a capable actor but his performance is a great one. He totally convinces as a man at the end of his tether dealing with a terrible situation and feeling unappreciated and adrift. There are other fine performances making this a gripping compelling drama, but never before has DicCaprio been as good as this.

There is a particularly thrilling scene where Costigan stalks Sullivan and the whole film sustains tension as both men try to blow each other’s cover first. It is creative and enthralling as the cop world is mirrored by the mob world. This is a first rate crime thriller with plenty of unexpected twists to keep the viewer riveted. Scorsese is back on form and elicits career best performances from his talented cast. I highly recommend it.

VIEW MOVIE TRAILER BELOW