ON December 29 1170 four barons of King Henry II's household murdered Thomas Becket, Archbishop of Canterbury at the cathedral altar, when under order only to arrest him.

Cut off from the channel ports, and therefore barred from returning to Normandy, the aristocratic assassins ran north and holed up in Knaresborough Castle for a year to mull over the "worst career move in English history" before presenting themselves to their ultimate judge and jury, the Pope.

That much is history, the rest is mystery. Paul Webb, a Cornish-born advertising copy writer turned playwright, stumbled across the knights' tale so long ago he cannot remember precisely when, but he knew there was a theatrical drama wrapped in the riddle of their year up north. Premiered in London in 1999, the play with Knaresborough in its title is belatedly making its northern homecoming, with a new ending.

In the tradition of copy-writing, Webb puts a spin on the knights' story but not to put their catastrophic deeds in a good light, but rather to study the individual motives of each assassin and their behaviour when cooped up together in extreme circumstances - a kind of Big Brother minus cameras.

The brooding Morville (Daniel Flynn), the irascible Fitz (Terence Beesley), his dry-witted former lover Traci (Dominic Mafham) and his new bit-of-rough crush, young Brito (the scintillating Steven Duffy) are observed on four nights over that 12-month stay, hence the play's title.

Stuck in Knaresborough, under the watchful, reproachful eye of the local community (represented by Paul M Meston's dignitary Wigmore and John the Visitor), the four knights are given succour, over-baked bread and minimal heat by the brave, resourceful single mother Catherine (the luminous Esther Hall), who has been deemed a witch by the community beyond for her actions.

The peeling bells of Canterbury, the ritualistic murder of a silent Becket and the solemn soundtrack of requiem song ensured the air was heavy with a darkly religious cloud, and yet Webb had surprised even himself by writing a comedy: in the manner of the 'waiting' dramas of Samuel Beckett's Waiting For Godot or Sergio Leone's spaghetti westerns , shot through with the visceral modernity (and "strong language") of Quentin Tarantino's Reservoir Dogs. There is the intellect of a Tom Stoppard or David Hare at play, albeit not matching their high-brow thought, because Webb is not averse to some Four Musketeers jollification while stretching themes of sexual jealousy, cruelty, personal conviction and political expediency to breaking point in Gemma Bodinetz's percussive, burning production.

Updated: 10:22 Monday, February 17, 2003