Adaptation of the English Medieval Mystery Plays, based on the York and Wakefield cycles, The Mysteries, were first performed in 1985 by the Royal National Theatre. Interviewed by Melvyn Bragg for BBC television in 2012, Harrison said: "It was only when I did the Mystery Plays and got Northern actors doing verse, that I felt that I was reclaiming the energy of classical verse in the voices that it was created for."
One of his best-known works is the long poem 'v.' (1985), written during the miners' strike of 1984–85, and describing a trip to see his parents' grave in Holbeck Cemetery in Beeston, Leeds, 'now littered with beer cans and vandalised by obscene graffiti'. The title has several possible interpretations: victory, versus, verse, etc. Proposals to screen a filmed version of 'v.' by Channel 4 in October 1987 drew howls of outrage from the tabloid press, some broadsheet journalists, and MPs, apparently concerned about the effects its "torrents of obscene language" and "streams of four-letter filth" would have on the nation's youth. Indeed, an Early Day Motion entitled "Television Obscenity" was proposed on 27 October 1987 by a group of Conservative MPs, who condemned Channel 4 and the Independent Broadcasting Authority. The motion was opposed only by MP Norman Buchan, who suggested that fellow members had either failed to read or failed to understand the poem. The broadcast went ahead and, after widespread press coverage, the uproar subsided. Gerald Howarth MP said that Harrison was "Probably another bolshie poet wishing to impose his frustrations on the rest of us". When told of this, Harrison retorted that Howarth was "Probably another idiot MP wishing to impose his intellectual limitations on the rest of us".