The Sinclair Sovereign was a high-end calculator introduced by Clive Sinclair’s company Sinclair Radionics in 1976. It was an attempt to escape from the unprofitable low end of the market and one of the last calculators Sinclair produced. Made with a case of pressed steel that a variety of finishes it cost between £30 and £60 at a time when other calculators could be purchased for under £5.