'Our dad helped to build the Colossus computer'

Peter Martin, right, is joining celebrations to mark the 80th anniversary of the Colossus code-breaking computer used in WW2

The family of an electrical engineer said it was "really quite extraordinary" to discover he had worked on the Colossus codebreaking computer in World War Two.

The contribution of Fred Martin at Bletchley Park’s secret wartime centre only came to light in 2012, almost 40 years after he died.

"It’s such a shame we couldn’t have conversations about it," said his son Peter Martin, who is attending an event at the National Museum of Computing on Saturday to mark the 80th anniversary of the world’s first electronic, digital computer.

His sister, Jane Martin, is hoping to meet other descendants of Colossus designer Tommy Flowers and those whose family members worked on the project.

Electrical engineer Fred Martin died in 1975, decades before his family discovered he had worked on the Colossus computer during WW2

Mr Flowers designed and built Colossus to help decipher encrypted German messages between Hitler and his generals, while Alan Turing and Gordon Welchman’s Bombe machine helped to crack the German Enigma code.

Both machines were credited with helping glean vital information that cut short the war and saved thousands of lives.

Mr Flowers and Mr Martin both worked as research engineers at the General Post Office, and Peter said his father "certainly worked with Tommy Flowers".

Jane and Peter knew nothing of their father's wartime achievements due to the Official Secrets Act.

"The house was full of electrical things. He made a TV for us, a hairdryer, an electric blanket. I knew how to rewire a plug from the age of about six," recalled Jane.

Fred Martin, second from right, pictured with other Post Office staff at RAF Hucknall

Peter said he had read quite a lot about the Colossus machine before discovering his dad’s involvement.

"The first time I saw Colossus, I noticed the metal framework on which the contraption was built was very similar to a framework dad had in the garage."

He said Mr Flowers and his team took "considerable risk in making the thing".

"Someone said 'You can't do that', and Tommy said 'You can - with valves'.

"There were a lot of problems to solve in terms of 'How do you make this work?'"

The family of Fred Martin (back row, centre) believe this photo was taken with his Post Office colleagues, and wonder if any others also worked at Bletchley Park

Jane said: "I remember asking dad what he did during the war – he said 'I worked on various radio stations and had a lot of fun with the Wrens, letting down people’s lilos as pranks'."

Jane and Peter are convinced their mother, who had died before the news came out in 2012, was also in the dark about her husband's work on Colossus.

A family friend, who worked in telecoms, had helped them to discover the truth.

"He found dad's name at Bletchley Park and got a certificate for us all.

"We were quite excited and really rather sad that we couldn’t talk to our father about it, so we quickly went up to Bletchley Park. A lot of what was there was familiar.

"It was really quite extraordinary when all those years later we should find out that he worked there," she added.