Veterans mark code-breaking machine's 75th anniversary

A team of 39 women who worked on Colossus, known as C Watch, pictured circa 1945

Veterans who worked on a code-breaking computer credited with shortening World War Two have reunited to mark 75 years since its creation.

Colossus was the world's first programmable computer and went into operation at Bletchley Park in 1944.

The machine was used to decipher encrypted messages sent between Hitler and his generals.

Former workers gathered at The National Museum of Computing where there is a working reconstruction of the machine.

Due to secrecy surrounding the work at code-breaking base Bletchley Park, many were unaware how important their role was.

For decades after, they were sworn to secrecy and could not talk about their former work.

Margaret Bullen was 17-years-old when she began working at Bletchley Park

Margaret Bullen was one of the women who worked on Colossus and attended the anniversary event.

She was 17-years-old when she started working at Bletchley Park.

"The first thing we did was sign the Official Secrets Act," she said.

"I don't think my parents knew what I did. They knew I was at Bletchley doing war work - I could've been making bombs for all they knew."

Lorna Cockayne said she is pleased the work she did at Bletchley is being recognised

Lorna Cockayne, who also worked on Colossus, said she enjoyed the work as her colleagues kept her company at a time her brothers were serving in the armed forces.

"I was pleased I did it and I'm more than pleased people know about it because we couldn't talk about it," she said.

Experts credit the work of the intelligence centre at Bletchley Park with shortening the war by two years.

Mrs Bullen said she is "very proud" of her work at Bletchley Park

Mrs Bullen said she was working at Bletchley Park when the war ended.

"I remember a chap in the office coming in one day and saying 'you can go home now - that war's over'."