This month marks the 70th anniversary of the invention of the first programmable electronic computer by telecommunications pioneer Thomas ‘Tommy’ Flowers MBE, a former employee of the General Post Office (BT’s forerunner).

Tommy was closely involved in designing the world's first programmable electronic exchange at Highgate Wood, London, which opened on December 12, 1962. This was a key milestone towards the opening of Empress Exchange in west Kensington - the world's first digital exchange - in 1968.

To celebrate Tommy's remarkable achievements, a life size bronze portrait bust of him has been unveiled at BT’s Adastral Park centre near Ipswich at an event attended by members of the Flowers family, inventor Trevor Baylis and representatives from BT.

The bronze bust - entitled A Portrait of Tommy Flowers - depicts Tommy at 38, when he produced his first operational ‘Colossus’ computer and was produced by James Butler MBE, RA, FRBS, one of the UK’s foremost figurative sculptors.

A Portrait of Tommy Flowers by James Butler MBE, RA, FRBS

Tommy’s role in helping WWII codebreaking first came about when he was contacted by Alan Turing, who was then working at the government's Bletchley Park establishment. Turing wanted Tommy to build a decoder for the relay-based Bombe machine, which Turing had developed to help decrypt the Germans' Enigma codes. Although the decoder project was abandoned, Turing was impressed with Tommy’s work, and introduced him to Max Newman who was leading the effort to break a German cipher.

In February 1943, Tommy proposed an electronic system using over 1,800 valves (vacuum tubes). Because the most complicated previous electronic device had used about 150 valves, some were sceptical that such a device would be reliable, including the Bletchley Park management who merely encouraged Flowers to proceed on his own. He did so, providing much of the funds for the project himself.

Tommy’s extremely dedicated team at Dollis Hill built the first machine in 11 months, and it was immediately dubbed 'Colossus' by the Bletchley Park staff for its immense proportions. The prototype, Colossus Mark 1, is believed to have been first shown to work on December 8, 1943, at Dollis Hill before being reassembled at Bletchley Park in January 1944.

Anticipating the need for more computers, a Mark 2 redesign using 2,400 valves was begun before the first computer was even finished. The first Mark 2 Colossus was put into service at Bletchley Park on 1 June 1944, and immediately produced vital information for the imminent D-Day landings planned for Monday 5 June (postponed 24 hours by bad weather).

Ten Colossi machines were completed and used during World War II in British decoding efforts, and an 11th was ready for commissioning at the end of the war. All but two were dismantled at the end of the war. The remaining two were moved to GCHQ where they “may have played a significant part in the codebreaking operations of the Cold War" They were finally decommissioned in 1959 and 1960.

L to R - Trevor Baylis, OBE, inventor; James Butler, sculptor; Kenneth Flowers (Tommy's son) and Sue (Tommy's daughter in law)

L to R: Trevor Baylis, OBE, inventor (who unveiled the bust); James Butler MBE, sculptor; Kenneth Flowers (Tommy's son); and Sue (Tommy's daughter in law)