Tristan and YseultKneehigh’s is a theatre of collaboration. In Tristan & Yseult, their 2003 show which is being revived in a world tour to mark its tenth anniversary, the sense of collective creativity which has run through all of the company’s best work is on full display; though director Emma Rice ensures that the whole remains cohesive, this is a piece which thrives on the relationship not only between the various practices, techniques and skills used in its creation, but the bond between performers and audience.

Integral to the work is a framing device which has the tragic love story of the titular characters being performed by members of the Club of the Unloved, who greet the audience directly on entry and continue to make reference to our presence throughout the performance. It’s a canny trick which serves to establish the running theme of contrasts – loved and unloved, intimate and epic, black and white – but which also involves the audience from the get-go by situating the action in the same room as them.

It’s not about making us complicit in the same way that a Shakespearean soliloquy might, nor about – though we are amusingly invited to blow up and release celebratory balloons in a wedding scene – promoting audience engagement for entertainment. Rather, this is a worthy acknowledgement of theatrical artifice, and recognition of the fact that theatre requires an engaged audience just as much as it requires a cast of performers. It’s a dynamic which, particularly on the thrust stage of Bristol Old Vic, feels healthy and refreshing, and which one feels might be adopted by directors of modern political drama to essential, revitalising effect.

The narrative, which follows closely that of pre-Arthurian legend, sees the Cornish King Mark unexpectedly falling in love with Yseult, the sister of his nemesis. But she loves, and is loved by, the mysterious French wanderer Tristan, whom Mark has welcomed into his court like a son. What unfolds is a love triangle of progressively tragic proportions, played out with dark wit, and great visual and musical panache.

Dosed up on love potion, Tristan and Yseult swing from the ropes which hoist the mainsail of a boat, assisted in their aerial acrobatics – as ever – by the anorak-wearing Unloved, who operate the pulley system. It’s sensual, it’s joyous, it’s dangerous, and it’s all the more thrilling for being able to see the machinations of the trick; it’s another nod to the self-conscious artifice of the work, but also a subtle reminder that the couple’s infatuation with one another has been synthetically rather than naturally stimulated. Those kind of layers exist to be peeled back at every stage of the evening, and work because they are supported by an exceptionally fine ensemble cast, most notably Craig Johnson, who inhabits both Morholt – King Mark’s Irish enemy – and the put-upon lady-in-waiting Brangian, with great skill.

Rice’s musical choices feel happily emblematic of her whole approach to the production, a combination of composed score from Stu Barker, alongside Wagner, Carl Orff, Nick Cave and the occasional rock ‘n’ roll standard make up a rich and varied tapestry of love won, love lost and love envied. The drawing together of diverse, eclectic inspirations and source materials to create a unified whole is clearly an area of Rice’s expertise, and is here executed to great theatrical effect. For its vision of how theatre can connect to audiences as much as for its tale of love and sorrow, this is a work of significance.

Tristan and Yseult is playing at Bristol Old Vic until 20 July. For more information and tickets, see the Bristol Old Vic website.