" Dirty tricks & Cunning stunts " was an instructional trials video hosted by Martyn Ashton and Martin Hawyes , who demonstrated and explained basic maneuvers . The video has a large comedic aspect , the premise being that trials moves are used to evade Hans Rey's evil henchmen , and the whole look is based upon poorly made 70's cop shows . For all that , the film was hugely influential and inspired many beginners to progress . It remains available from Chilli Video and was voiced by Patsy Kensit .