In 1979, Clive Sinclair lost seven million pounds of investor money, was ousted from Sinclair Radionics, and walked away with a 10,000 pound severance. By 1983 he was making 14 million pounds in profit and receiving a knighthood. This episode traces the ZX Spectrum and the eccentric inventor behind it, from the world’s first pocket calculator and the failed Black Watch to the sub-100 pound ZX80, the 1.5 million-selling ZX81, and the April 1982 Spectrum launch.

We look at Sinclair’s refusal to do market research, his fear of Japanese competition, Richard Altwasser’s two-layer display that produced attribute clash, Rick Dickinson’s flat black case with a membrane keyboard reviewers likened to dead flesh, the mail-order backlog made worse by a Dundee factory holiday, and the price cut at peak sales that crushed rivals. Then comes the fall: the rushed Sinclair QL, the underpowered C5 electric tricycle, and the 1986 sale of the computer line to Alan Sugar’s Amstrad for five million pounds.

• Why ordering 100,000 sets of ZX80 components on a hunch was either genius or recklessness
• How single-key BASIC tokens saved memory and shaped a generation of efficient coders
• Why the UK’s cassette-based bedroom coding scene sailed through the 1983 American crash
• How the QL and C5 failures drew repeated rebukes from the Advertising Standards Authority
• Whether the Spectrum’s triumphs and the C5’s disaster were two sides of the same coin