Sinclair Research | Code Like It's 198x

Sinclair Research was the Cambridge computer company of Sir Clive Sinclair, which he built from 1979 out of the wreckage of his earlier company, Sinclair Radionics. The registered company is older: it was incorporated in 1973 as Westminster Mail Order Limited, carried five names, and outlived the computer business by almost forty years before it was dissolved in 2025. In three years it produced the three machines that made its name: the ZX80 (1980, £99.95 built), the ZX81 (1981, £49.95 kit / £69.95 built) and the ZX Spectrum (1982, £125 / £175). Together they put programmable computers into hundreds of thousands of British homes.

The Spectrum was the success. By Easter 1983 the company was selling 12,000 a week, and it still took over 40 per cent of the British market in 1986. The stumble was the Sinclair QL (1984), a 68008-based business computer announced before it worked and delivered four months late in a state Sinclair User called bug-ridden. On 7 April 1986 Sinclair sold the computer business, and the right to the Sinclair name on computers, to Alan Sugar’s Amstrad for £5 million. Amstrad continued the Spectrum line with the +2 and +3. The company itself carried on under Sir Clive, making other things.

Before Sinclair Research

Sinclair Research was Clive Sinclair’s third attempt at a high-technology company, and the story starts with the failure of the second.

Sinclair Radionics, formed in 1961, made amplifiers, pocket televisions and then calculators. Chris Curry joined in 1966; Nigel Searle in 1973. The Black Watch, a digital wristwatch, lost the company £355,000 in 1976, and that year the National Enterprise Board, a government investment body, took a 43% stake for £650,000. It put in more money in 1977, the year the calculator market collapsed. Radionics also designed a microcomputer that it sold on to Newbury Laboratories; it reached buyers under Grundy in 1982 as the NewBrain.

The board wanted to concentrate on measuring instruments; Sinclair wanted to keep building his pocket television. His separate venture with Chris Curry, Science of Cambridge, was already advertising the MK14 kit in March 1978, before Sinclair’s 1979 departure from Radionics. Curry left to set up Acorn, which went on to win the contract to build the BBC Micro. Science of Cambridge was renamed twice, first to Sinclair Computers and then to Sinclair Research. (Science of Cambridge, Wireless World, March 1978, p. 113.)

Acorn is sometimes described as founded by Sinclair Research alumni. The order runs the other way: Curry left the predecessor company, and Acorn was trading before the Sinclair Research name existed.

Five names, one company

The period accounts date Science of Cambridge differently: Sinclair User puts it in 1979, CRASH at the tail of the Radionics collapse. The public register shows that the name went onto a company that already existed.

Company 01135105 was incorporated on 19 September 1973 as Westminster Mail Order Limited, and carried five names before it was dissolved:

Registered as	From
Westminster Mail Order Limited	1973 (incorporated 19 September)
Sinclair Instruments Limited	1976
Science of Cambridge Limited	1977
Sinclair Computers Limited	1980
Sinclair Research Limited	1981

So the company that sold the ZX Spectrum was eight years old when it launched the machine, and was first registered to sell things by post. The register gives every change of name the same day, 31 December, so only the years are shown here.

The company also outlived the machines by four decades. The computer business went to Amstrad in 1986; company 01135105 was not dissolved until 14 October 2025.

The cost-reduction playbook

Sinclair Research’s signature was getting as much as possible out of the cheapest possible parts. The repeated tricks:

Membrane and rubber keyboards instead of mechanical typewriter keys. Rick Dickinson’s membrane keyboard for the ZX81 was, Sinclair User said in 1982, “largely responsible for the low retail price of the product”; the Spectrum’s keys were moulded rubber.
Custom ULA chips that did the work of many. In the ZX81 one Ferranti chip replaced 18 of the ZX80’s, leaving four chips in the whole computer. The Spectrum’s ULA handled video, memory timing, the keyboard and tape input and output.
The family television as the display, through an RF modulator, so no monitor to buy.
Cassette storage rather than disk: most households already had a tape recorder.
Mail order. The ZX80, ZX81 and Spectrum all started life as mail-order products. The coupons in Computer & Video Games in November 1981 give the address as 6 Kings Parade, Cambridge, CB2 1SN, FREEPOST, no stamp needed. The ZX81 later reached the high street through WH Smith. Mail order also means the customer pays before the machine ships, which mattered when deliveries slipped.

The other pattern: late, quirky, returned

The cost-reduction story is the one usually told. Running alongside it, from the Spectrum onward, is a second pattern that the trade press named at the time.

Sinclair User, reviewing the company’s history in June 1986, put it plainly about the Spectrum’s own launch: mail order only, “a disastrous operation which left early purchasers waiting two months for delivery. The early machines were operationally quirky and many of them were returned by customers. The pattern of late deliveries and unreliability had begun to emerge.” The same paragraph concedes what kept the company alive anyway: “notwithstanding, the machine was outstanding value”.

The peripherals fared worse.

Microdrives (£49.95, 1983), one of Sir Clive’s pet projects, were “badly savaged by the press”: they initially took longer to load than cassette tape, the tape loops stretched and corrupted what was stored on them, and the drives were unreliable.
ZX Interface 2, with its ROM cartridge slot and two joystick ports, was withdrawn within two years, and only a handful of ROM games were ever produced for it.

The QL

The Sinclair QL is usually summarised as an ambitious 68008 machine let down by Microdrives. The contemporary account is harsher, and it is about a launch date rather than a design. What follows is what the QL did to the company; the machine itself has its own entry.

Sinclair announced the QL in January 1984 at £399. Sinclair User: “in a desperate hurry to beat the launch of Apple’s Macintosh, the QL was rushed out in an only partly finished form.”

What followed, in order:

The machine shown to journalists at the launch “was hardly a QL at all”. The operating system on display, written by GST, was replaced soon after by a Sinclair-commissioned system called QDOS, which Sinclair User said was “widely held to be inferior”.
Machines arrived four months after the launch, bug-ridden, and with “half the operating system left hanging out of the back” on an external board.
By May, Sinclair Research was holding £5 million against 13,000 orders, of which only a few hundred had been delivered. The company offered apologetic incentives, a free RS-232 lead among them.
A reliable working QL did not appear until late summer 1984, by which point Sinclair had been criticised by the Advertising Standards Authority and, in Sinclair User’s phrase, “hounded by customers”.

1985: the year it came apart

October 1984 to January 1985. Distributors had “wildly overstocked” the Spectrum Plus for Christmas, and when the home-computer market nose-dived in January, Sinclair Research “became desperate for money, just when nobody wanted to re-order”. The planned stock-market flotation was cancelled. In 1984 a 10% float had valued the company at over £130 million.
January. The C5 electric tricycle, launched by a separate company, Sinclair Vehicles, “did nothing to bolster Sir Clive’s reputation”; Sinclair User judged that it “branded him in the media as a kind of ‘mad boffin’”. Production was scaled down and stopped.
Summer. Robert Maxwell announced a takeover of Sinclair Research. In September Acorn User noted that Sir Clive had just turned up as a cartoon character in the “Jane” strip of Maxwell’s own Daily Mirror, a strip the paper said had been commissioned ten weeks earlier, and called the timing “pure coincidence”. By autumn Maxwell’s board had rejected the deal and Sinclair was on his own again.
October. A financial rescue package satisfied the creditors, who by then included Thorn EMI, Timex, Barclays Bank and AIB.
Christmas. Most of the debt was repaid through a £10 million bulk purchase of Spectrum Pluses by Dixons, so a company that had started out selling by post was saved by a single retailer’s order.
February 1986. At the launch of the 128K Spectrum, Sinclair predicted his company would again be “the jewel in the British Computing crown”.

Less than eight weeks later he sold it.

Cambridge, and the people who left

Sinclair Research was based at 6 Kings Parade, Cambridge, in the city centre near the university. Industrial designer Rick Dickinson designed the ZX81, the Spectrum and the QL. The software came from outside: Sinclair BASIC was written by the Cambridge firm Nine Tiles, and the Spectrum’s ROM by Steven Vickers and John Grant on contract from it.

The Spectrum’s designers did not stay. Richard Altwasser, who designed its hardware, left Sinclair in 1982, and Steven Vickers left Nine Tiles, to found Jupiter Cantab together, and their advertising said so in as many words: “leading computer designers Richard Altwasser and Steven Vickers… after playing the major role in creating the ZX Spectrum they formed Jupiter Cantab to develop their latest brainchild the Jupiter Ace”.

The Ace shipped at £89.95 by mail order, with Forth rather than BASIC in ROM. ACE magazine, looking back in 1990, remembered it as “the only home computer to sport Forth as its inbuilt language. This proved to be its downfall.” Altwasser had left the company by 1983, and by the end of that year Jupiter Cantab was in liquidation, having sold about five or six thousand Aces.

ACE filed Jupiter Cantab among the Cambridge companies as “the ill-fated splinter group from Sinclair Research”.

7 April 1986

CRASH’s John Minson went to the press conference and caught the tone in a sentence: “If it had happened a week earlier we’d all have thought it was an April Fool, but at the hastily called press conference at noon on 7th April there was no laughter — just the smiling face of Amstrad’s Alan Sugar and the slightly more restrained features of Sir Clive Sinclair.”

£5 million, for the worldwide rights to sell and manufacture existing and future Sinclair computers and the Sinclair brand name for computer products. Amstrad also bought the existing stock. What it got:

Control of the Spectrum 48, Plus and 128, and first option on Pandora, the portable then in development.
A warehouse. Sinclair User reported that Amstrad sold over 20,000 rubber-key 16K and 48K Spectrums, along with most of the remaining QL stock, to an overseas distributor in a deal “worth more than £2 million”.
The QL, which it did not want. Amstrad announced within weeks that it would not pursue the machine, and tried to raise a quarter of a million pounds by selling the remaining 19,000 units and throwing in the manufacturing rights free. Interested parties included Timex and the QL user group Quanta; none of them came up with the cash.
Loki, a super-Spectrum “well advanced at the time of the Amstrad take-over”, named for the Norse god. Sir Clive told Sinclair User that summer that it was abandoned “so far as we are concerned”, and no Loki machine was ever released.

For scale: Amstrad’s profits for the last six months of 1985 came in above £27 million, so the purchase cost it roughly one month’s profit.

The gap between the two men was not only financial. Your Sinclair noted the sight of “the man who did more than anyone to fulfil his vision of a computer in every home, sitting next to Amstrad boss Alan Sugar, who’s called the Spectrum a pregnant calculator”. Amstrad’s stated plans were to move Sinclair machines firmly into entertainment, keep them software-compatible, and, in Your Sinclair’s summary, “study why Sinclair products have gained a reputation for poor quality”.

Legacy

The ZX Spectrum is Sinclair Research’s best-known legacy, still commanding over 40 per cent of British machines sold as late as 1986, on Sinclair User’s figures. It also created an industry around itself. Sinclair User counted the “cottage industries” that sprang up to supply the ZX80 and ZX81 with software, add-ons and publications, and CRASH pointed out that dk’tronics and Quicksilva, both still active in the Spectrum market in 1985, began by making memory expansions for the ZX80.

Sinclair User’s own summary, written eight weeks after the sale, makes the argument in terms of what the machines cost rather than what they did: “Without his sub-£100 micros the Commodore 64 might still be £350 and Amstrad certainly wouldn’t ever have become involved in home computers.”

The Spectrum was not the best-made computer of its time, and Sinclair’s own trade press said so at length. It was cheap enough to be in the house, and being in the house is what produced a generation who could program.

After the sale Sinclair Research went on without computers. In 1992 it announced Sir Clive’s Zike electric bicycle, at £499. Sir Clive died in 2021, and the company outlived him by four years.

Sources

Sinclair User issue 51, June 1986, p. 47: the company history and timeline (July 1979 founding; Radionics; Curry and Searle; Black Watch; NEB stake; Newbury Labs and the NewBrain; product prices; the Spectrum’s mail-order launch; Microdrives and Interface 2; the QL; the 1985 crisis, Maxwell, the creditors and Dixons; the 128K launch; the 40 per cent share; “sub-£100 micros”).
Sinclair User issue 51, June 1986, pp. 7–8: Amstrad’s sale of Spectrum and QL stock; Loki; the QL stock of 19,000 and the interested parties.
Sinclair User issue 53, August 1986, p. 55: Sir Clive on Loki.
Sinclair User issue 46, January 1986, p. 88: Altwasser designed the Spectrum hardware; Vickers wrote its software on contract from Nine Tiles; the ZX81 in WH Smith; the “cottage industries” around the ZX80 and ZX81.
Sinclair User issue 5, August 1982, pp. 55–56: Rick Dickinson and the ZX81 membrane keyboard.
Edge issue 137, June 2004, “The Rick Dickinson guide to classic computer design”: Dickinson designed the ZX81, Spectrum and QL.
CRASH issue 15, April 1985, pp. 86–87, and issue 16, May 1985, pp. 126–127, “The Sinclair Story”: Science of Cambridge and the NEB split; mail order; the ZX81’s Ferranti chip; dk’tronics and Quicksilva’s ZX80 memory add-ons.
CRASH issue 28, May 1986, pp. 10–12, John Minson on the Amstrad sale, including Amstrad’s profits and what it controlled.
Your Sinclair issue 6, June 1986, p. 11: the sale and Amstrad’s plans.
Chris Smith, The ZX Spectrum ULA: How to Design a Microcomputer (ZX Design and Media), chapter 7: what the Spectrum’s ULA does, and the ROM’s authors.
Computer & Video Games issue 1, November 1981, pp. 22–23: Sinclair Research advertisement and coupon (prices, Kings Parade address).
Computer & Video Games issue 12, October 1982, p. 26: Jupiter Cantab advertisement.
ACE issue 28, January 1990, p. 33, and issue 33, June 1990, p. 18: the Jupiter Ace and Jupiter Cantab.
Ace User issues 3 and 4 (1983), the Jupiter Ace user club newsletter: Altwasser’s departure and Jupiter Cantab’s liquidation.
Acorn User issue 38, September 1985, p. 11: Sir Clive in the Daily Mirror’s “Jane” strip.
PC Review issue 7, May 1992, p. 9: the Zike, made for Sinclair Research.
Companies House, company 01135105, Sinclair Research Limited: incorporation, previous names and dissolution. https://find-and-update.company-information.service.gov.uk/company/01135105