at the end of series 2, citing a desire to pursue solo projects, although there had been an increasing degree of creative tension between him and Milligan. Milligan blamed his breakdown and the collapse of his first marriage on the sheer volume of writing the show required. His then ground-breaking use of sound effects also contributed to the pressure. All this exacerbated his mental instability that included bipolar disorder, especially during the third series. The BBC however made sure he was surrounded by accomplished radio comedy writers — Sykes, Stephens, Antrobus, Wiltshire, and Grafton — so many of the problems caused by his ill health were skilfully covered over by composite scripts. Many senior BBC staff were variously bemused and befuddled by the show's surreal humour and it has been reported that senior programme executives erroneously referred to it as The Go On Show or even The Coon Show. The show's title was inspired, according to Spike Milligan, by Alice the Goon, a character from the Popeye comic. Several of the Goons' nonsense songs were recorded in the late 1950s such as the "Ying Tong Song", number 3 in the UK Singles Chart in 1956. The radio show had high audience ratings in Britain at its peak; tickets for the recording sessions at the BBC's Camden Theatre (now known as KOKO) in London were constantly over-subscribed and the various character voices and catchphrases from the show quickly became part of the vernacular. The series has remained consistently popular ever since, with the show being broadcast weekly by Australia's ABC network as late as 2012. The show is also broadcast on BBC Radio 4 Extra. The scripts exist mostly in fan-transcribed versions via dedicated websites. Although three books were published containing selected scripts, they are out of print, and typically available only in libraries or second-hand. Some more recent biographical books contain selected scripts. There were 10 series in total, plus an additional series called Vintage Goons, recorded at the same time as the eighth series, which featured recordings of redevelopments (by Milligan) of short sketches from early shows which had not been recorded by transcription services. The first series had 17 episodes plus one special, Cinderella (1951); the second series had 25 episodes, (1952); the third series had 25 episodes plus one special - The Coronation Special (1952–53); the fourth series had 30 episodes plus one special, Archie In Goonland