The launch of the ZX81 was catalysed in part by the British Broadcasting Corporation Computer Literacy Project's plan to produce The Computer Programme TV series, to be broadcast in 1982, aimed at popularising computing and programming. The BBC intended to commission an existing manufacturer to provide it with a BBC-branded home computer to tie in with the series. When Clive Sinclair heard of the project in December 1980, he wrote to the BBC informing them that he would be announcing a new version of the ZX80, to be called the ZX81, in early 1981. It would remedy some of the ZX80's deficiencies and would be both cheaper and more advanced. Sinclair wanted the ZX81 to be a candidate for the BBC contract and lobbied for its adoption. He pointed out that there were already 40,000 users of the ZX80 and that by the time the series was broadcast there were likely to be upwards of 100,000 ZX81 users (which turned out to be an underestimate by over 400,000 – an indication of how the ZX81's success exceeded even Sinclair's expectations).