In late ’60s Chicago, 19-year-old car thief William O’Neal (Lakeith Stanfield) turns FBI informant to infiltrate the Black Panther Party and take down its charismatic leader Fred Hampton (Daniel Kaluuya).

Right on time and much too late, this tragic true story is the flipside of Mississippi Burning; an unflattering exposé of the FBI under J. Edgar Hoover (a grotesque Martin Sheen). Shaka King’s film goes beyond the textbook reading of the Panthers as a terrorist group to show the Illinois chapter feeding children, planning hospitals and forming a Rainbow Coalition with local white activists, while the Bureau terrorise them and the young informant using the cowardly tactics of the racist.

The picture does not judge O’Neal’s actions, portraying him as a victim of his FBI handler (the great Jesse Plemons). Stanfield is a brilliant ball of nervous energy, conflict, fear and guilt always written across his face. The Oscar-winning Kaluuya is electrifying in oratory scenes and sensitive in tender moments with Deborah Johnson (Dominique Fishback), their touching love story loaded with preemptive heartbreak. Dominique Thorne also makes a huge impact in a minor Panther role.

Every scene crackles with hair-trigger tension and political import, even the aforementioned intimacy between Hampton and Johnson; people being watched for trying to effect social change. That uneasy, unshakeable atmosphere is omnipresent and oppressive, building to a devastating climax and illuminating epilogue. The eerie jazz soundtrack includes Rahsaan Roland Kirk, Gil Scott-Heron and Bill Evans, with inspired use of Duke Ellington’s haunting Fleurette Africaine.

Judas and the Black Messiah is a vital hot-wire of a movie about the people who dare stand up to the badge, and the protection afforded those who hide behind it.