1947-49: Manchester Mark 1 hardware development period.

1948 June: SSEM (the "Baby") operational. World's first stored program computer.
1949 April: Manchester Mark 1 working in intermediate form.
1949 October: Manchester Mark 1 fully operational. First machine with fast random-access two-level store (RAM + Disc).

1951 February: Ferranti Mark 1 first installation. First commercial computer.

1951-54: Meg hardware development period.

1952-55: Transistor Computer hardware development period.

1953: Transistor Computer Prototype operational. First transistor computer.

1954: Meg Prototype operational. Floating-point machine.

1955: Extended Transistor Computer operational.

1956: Met-Vickers MV 950 first installation.

1957 August: Ferranti Mercury first installation.

1956-62: Ferranti Atlas (formally Muse) hardware development period.

1962 December: Ferranti Atlas first installation operational.

1966-74: MU5 hardware development period.

1972: First run of MU5.

1974: MU5 machine complex fully operational (hardware and software, all three machines -- MU5, ICL1905E and PDP11/10).