The new Sinclair DM235 digital multimeter. 3.5 digits. Under £50!

Sinclair Radionics, the company that was based in St. Ives, Cambridgeshire, was in some financial difficulties during the mid 70s, and was part-nationalised by the National Enterprise Board. 

During this time, Clive Sinclair set up a shell company that would eventually become Science of Cambridge, and then Sinclair Computers. He had entrusted Chris Curry, who would go on to set up Acorn Computers, with the task of getting this company up and running. 

Meanwhile, back in St. Ives, Radionics was doing a steady trade in scientific instruments, of which this is an example. Apparently, these instruments were known for their reliability, compared to the often notorious unreliability of many of Sinclair's other products.

After the NEB had bailed Sinclair out, it had wanted the company to return to its instruments roots, rather than move into micro televisions or electric transportation. This was largely because it though Sinclair wouldn't be able to hold its own against the threat of the Japanese invasion. 

It was this disagreement over direction which triggered Sinclair's departure from the company he had founded[source: "Clive Sinclair: interview", Practical Computing, July 1982, p. 56].