Midsomer Murders and Minder regular Nicholas Day is a far cry indeed from his cosy small-screen image as he writhes stark naked on the stage of the Royal Shakespeare Theatre while fellow actors simulate sodomy upon him with outsize sex toys. The abuse at last concluded, the implements are then pushed into the faces of members of the audience.

This nauseating scene immediately precedes the interval in the Royal Shakespeare Company’s controversial revival of Peter Weiss’s shocker Marat/Sade. It is hardly surprising that substantial numbers of theatregoers are choosing not to return for the second half.

Translated from the German by Geoffrey Skelton and rendered into (rather bad) poetry by Adrian Mitchell, a former Oxford Mail drama critic, the play was a significant success for the RSC, under director Peter Brook, in its 1964 ‘Theatre of Cruelty’ season. Its Brechtian ‘song and dance’ staging and revolutionary tone matched the mood of the moment.

“I haven’t seen the play but I have read the title,” was an oft-heard witticism at the time. This certainly tells it like it is, being in its full form The Persecution and Assassination of Marat as Performed by the Inmates of Charenton under the Direction of the Marquis de Sade.

Bringing it back in the RSC’s 50th birthday season, there is implicit acknowledgement of its status as an important staging post on the road to total freedom in the theatre such as we enjoy today. Presented as a 1960s period piece, depicting the clash between Marxist and Freudian thinking, it might have worked well. But director Anthony Neilson has added further complications by updating the action to the present day, with obvious references to unrest in London and the Arab world.

The sick and deluded of Charenton are controlled by the asylum director Coulmier (Christopher Ettridge) by means of mobile phones. Not very well controlled, since they remain free (as we see) to masturbate incessantly, indulge in coprophilia and torture poor Marat (Arsher Ali) in the way depicted above.

Other shocking scenes include a repeated Taser gun attack on the drag-clad De Sade (Jasper Britton) by the narcoleptic inmate playing Charlotte Corday (Imogen Doel) — who gets to shoot rather than stab the bath-bound Marat — and simulated fellatio with a visiting bishop.

The misrule is in large part supervised by the Herald, who is played in dominatrix style by the diminutive Lisa Hammond. She gets to speak some of the most clunking of Mitchell’s couplets while whizzing around the stage in a smoke-emitting electric wheelchair, looking a bit like the Daleks’ sinister creator Davros.

Until November 5. Box office: 0844 800 1114 (www.rsc.org.uk).