In 1920, the company moved from London to Letchworth, Hertfordshire; it was also at this point that it started manufacturing its own machines, rather than simply reselling Hollerith equipment.
In return for the exclusive right to market Hollerith equipment in Britain and the Empire (excluding Canada), BTM paid 25% of its revenues to the American company by way of royalties.
This became an ever-increasing burden as the years progressed; BTM attempted to renegotiate the agreement on several occasions, but it was only finally terminated in 1948.
The machines had a 2 kilobyte drum memory and 1000 valves, and could use punched cards for input and output, or drive a printer.
[8] In 1959 BTM merged with former rival Powers-Samas to become International Computers and Tabulators Limited (ICT).