Since then many additional improvements have been made to the production facilities at Wembley. Four mobile outside broadcast units are houses here, while modern videotape and telerecording facilities enable the most economical use to be made of the studios. The most ambitious extension was the 14,000 square foot studio 5 which first went on air in June, 1960. With space enough to contain a complete audience of 500, studio 5 has been the scene of many of Rediffusion Television’s major productions. This studio, one of the world’s largest specially built for television, has an unusual design. It can be used in two ways: either as one huge studio with up to eight cameras directed from a single control room, or as two self-contained studios, 5a and 5b. When this happens two massive 25-ton steel doors are lowered at a speed of one foot per minute. The connecting side doors are closed, and each sound-proof section can then be used independently for two quite separate productions.