Thats not the phrase asked for Hippy and actually "Anything can happen in the next half hour" is said by Commander Shore during the opening titles of "Stingray".
Many BBC comedy shows had both radio and tv versions. Sometimes the radio show was remade for tv and sometimes the other way round. Whacko certainly existed in both forms, as did many others such as 'the Likely Lads' and 'Fawlty Towers'.