Ipswich’s bunker was designed as a county-wide centre in the event of a catastrophic disaster, including a nuclear attack.

Had the country come under attack, the man in charge during the 1970s and 1980s would have been Clifford Smith, chief executive of East Suffolk, and from 1974 Suffolk, County Council.

He was designated “county commander” and in the even of a major emergency he would have had control over much of life in the county.

Mr Smith said: “I would have chosen who went into the bunker – although we often speculated on whether those selected would actually have gone in there or whether they would prefer to see things out with their families!”

The Ipswich bunker was not very large: “There was room for about 12 people, but that would have been fairly crowded.

“There was a small kitchen and a couple of toilets, but it wasn’t the kind of place you would have wanted to be shut up for very long!” he said.

The most important feature of the bunker was its secure radio connection to keep in touch with the outside world.

“The government bunkers, like those in Essex, were much larger and we would have been in touch with them but this was the Suffolk control centre.”

Mr Smith would have chosen the team to go into the bunker with him. There would have been a senior police officer (possibly the chief constable), the fire chief, a hospital boss, representatives of other services, possibly the county surveyor, and a representative of the WRVS who would help to co-ordinate relief efforts above ground.

“Everyone would be there for a reason,” he said. “It wouldn’t be a case of bringing down members of your family for safety.”

The bunker was ready for use in many emergencies, not just nuclear war. It was used for exercises and for occasional major incidents which hit Suffolk.

Mr Smith said: “The last time I can remember using the centre was during the aftermath of the great storm in 1987.

“It’s radio links were vital in the days before mobile phones. Those of us based there could keep in touch with what was happening around the county.”

Today there is an emergency control centre that can be set up at police headquarters – it was used to monitor the situation during December’s surge tide – but it is not an underground bunker because the threat of all-out nuclear is not considered as serious since the end of the Cold War following the fall of the Berlin Wall in 1989.