With Baskervillian barking in the background and devil-tarot cards flickering across the screen, Lady Macbeth’s cadaverous face curls into a nefarious grin. After slathering vermilion lipstick on his stubbled mouth, Lady Macbeth — or rather, “Ladyboy” — and a cavalcade of droog-like witches get together for a spot of skull-duggery, cellblock C-style.

Not classic Shakespeare, for sure. This is Mickey B, the Educational Shakespeare Company’s (ESC) adaptation of the jet-black tragedy Macbeth, shot in Maghaberry Prison in Northern Ireland.

Twenty-four of the 25-strong cast are still behind bars — and probably will be for a long time. In this version of Macbeth, usurpations are carried out with shanks, paid for with packs of Golden Virginia tobacco and the poison of choice is LSD, not hemlock.

Maghaberry is a maximum security facility and a lot of the inmates are lifers, so there was no way to film outside the prison. That makes the hour-long feature claustrophobic and, at times, uncomfortable viewing.

The jail’s brickwork and joinery rooms were transformed into a monochrome set over two weekends and its construction necessitated co-operation between prisoners and prison officers. The scene in which King Duncan is found slain in his bed takes place in a replica of one Maghaberry’s 745 single cells; 4mx2m with an open top to allow high-angle shots.

There was a frisson of disgruntlement in the Northern Irish press about the close-to-the-bone nature of the project, some of which centred on the decision to film one of the more macabre of Shakespeare plays.

But Mickey B director Tom Magill (who is also ESC’s artistic director) believes the logic behind producing a film based on Macbeth — the tension of which resonated strongly with the detainees, many of whom experienced brutality on the streets of Belfast — is that it helps on the long road to rehabilitation.

Along with organisations like the Koestler Arts Trust, which holds an annual prize for prisoner artwork and literature, and Billy Bragg’s Jail Guitar Doors, ESC’s aims to dispel the idea that, no matter what, “prisoner” is an indelible identity.