He was part of the team that helped to significantly shorten the length of the second world war and as Roy Robinson turns 90 today, he shows no sign of slowing down.

The great grandfather from Norwich was one of the engineers based at the code-breaking centre Bletchley Park during World War Two.

Having worked as a trainee telephone engineer for the then GPO in Norwich, he was sent to the Buckinghamshire mansion to help build and maintain the code-cracking machine Colossus – the world's first electronic computer.

Colossus computers were used to break high-level German communications which had been encrypted using complex cipher machines,

To celebrate Mr Robinson's milestone, a special cake was made in the shape of a German Enigma cipher machine and friends and family joined him at his home in Greenways, Eaton.

The celebrations will continue today and into this week.

Fit and active Mr Robinson, who lives on his own after losing his wife Norah nearly six years ago, said: 'I don't feel any different, I feel the same. I still drive, I've still got my sight and my hearing and although my memory isn't as good as it used to be, my joints are good. I've been very fortunate really.'

Mr Robinson, who has nine grandchildren and 11 great grandchildren, said when Bletchley Park first opened, the staffing levels could be measured in dozens but by the time they had finished, there were 20,000 people.

'We were all sworn to secrecy and it was some 12 or 15 years after the war had finished that I even told my wife,' said Mr Robinson, who has three sons, David, 66, John, 62, and Tim, 58.

'We knew what we were doing was important but we didn't know how important.

'They reckon it took two years off the length of the war, all the message deciphering. A message could take a month to decipher by hand but the computers were hundreds of times quicker – they could decipher the codes in hours.'

Mr Robinson's work at Bletchley Park continued after the end of the war until 1946 while he helped dismantle all the code-breaking equipment under the prime minister's instructions. He then went back for Norwich telephones and ended up as general manager for the Norwich area for British Telecom until he retired aged 61.

'I don't know what keeps me in good health, I've been fortunate really. I'm looking forward to my 100th now.'

Do you know someone celebrating a special milestone? Call reporter Kate Scotter on 01603 772326 or email kate.scotter@archant.co.uk.