This one was commissioned to celebrate ten years of our celebrated Time Lord, and it pitches the "Doctor" (Jon Pertwee) against his most deadly foe yet! Indeed such is the peril faced by the entire galaxy, the folks on "Gallifrey" have broken just about every rule of time there is to provide him with the support of his earlier iterations - Patrick Troughton and William Hartnell. What's the problem? Well it seems that anti-matter is gradually taking over the universe and the process looks like it will quite literally lead to the big bang. With "Jo" (Katy Manning) and the redoubtable "Brigadier" (Nicholas Courtney) on their team, the three must rally together and use all of their accumulated wisdom and guile if they are to defeat their ultimate nemesis - "Omega"! This is one of my favourite outings for the "Doctor" that's well enhanced by a strong and amiable contribution from the sightly eccentric Troughton as they face a baddie that exudes loads of teatime menace. We still get to film in the BBC quarry for some of this, but that is mixed effectively with some decent visual effects and a really solid story that is well paced and poured into four episodes that don't hang around. True - some of the monsters do look like they've just escaped from a wine gum factory, but with timelines crossing and critters appearing and disappearing all over the shop and quite a bit of wit in the script, this makes for an enjoyable hour of time travel adventures, revenge and an annoying recorder (flute not tape). Good fun, this.