Though Doctor Who's spiritual home is now in Cardiff, for much of its lifespan it was produced in Great Britain's capital city. Even today, London locations are sought for key sequences, giving the sci-fi action a sense of gravitas. After all, would the Loch Ness Monster have looked as impressive coming out of the River Trent? It's a marvellous setting, but of course not! Only the fetid soup of the Thames could have struck such a chord with audiences around the world in Terror Of The Zygons. Some of the show's most memorable alien environments - from the jungle in Planet Of Evil to the Tranquil Repose cryo-facility in Revelation Of The Daleks - were hurriedly shot within the confines of the old Television Centre, West London. So it's safe to say, wherever he went in time and space, the Doctor wasn't far from the chimes of Big Ben. But which south east-centric tales stand out from the rest, utilizing the the urban sprawl to the maximum, and making a much-loved, much-loathed land mass a central part of the adventure? You're about to find out. The bow bells of Big Ben have sounded... or is it the Cloister Bell? Whichever the source, it's calling time on the tetchy Time Lord's biggest and best London-based escapades...