Plymouth's 1950s city centre in preservation plea
English Heritage has called for the whole of Plymouth city centre to become a designated conservation area.
It said Plymouth was "unique" as the only British city to have the whole of its centre completely rebuilt after it was heavily bombed during World War II.
The heritage organisation said the rebuilt city was "as representative of its time as Bath or York".
The city council welcomed the debate but said history must sit alongside "planning a prosperous future".
Plymouth has more listed 1950s buildings than anywhere outside London.
Simon Thurley, chief executive of English Heritage, said: "It is a unique place.
"There was no other other English city that was bombed as badly as Plymouth was in the second world war.
"The night of 21 March 1941 basically obliterated the entire centre of the town and what happened afterwards was actually pretty visionary.
"We believe this represents a phase in our national history that should be cherished and looked after.
"The buildings have really strong qualities, they are very nicely designed with broad streets with trees planted down the middle.
"They are recognised by historians as being amongst the best buildings built anywhere in the 1950s."
'Preserve in aspic'
The current city centre was designed after the war and gave the city centre a new linear layout with intersecting wide boulevards giving an uninterrupted view up to the Hoe and the sea.
One Plymouth resident who lived through the war told BBC Radio Devon: "When I was a little girl it was only Nissen huts and goodness knows what.
"It was a great thing for us as teenagers to see the city being built up so beautifully."
But another resident described the buildings as "grey, bland concrete".
Plymouth City Council said: "This is an interesting debate, however English Heritage must recognise that there needs to be a careful balance between preserving our past and planning for a prosperous future.
"We cannot preserve the city centre in aspic and need flexibility to enable the centre to fulfil its role as a lynch pin to the local economy.
"We do, of course, acknowledge the importance of buildings that contribute to Plymouth's unique history and these are referred to in great detail in the City Centre Action Plan, which guides development and planning decisions made around the city centre."
English Heritage has previously locked horns with Plymouth City Council, which had planned to demolish the 15-storey Civic Centre, built in 1962, to save money.
In 2007 English Heritage gave it Grade II listed status to protect it from the bulldozers and the building is currently for sale.
Mr Thurley said the council chamber inside the centre was a "really outstanding landmark" comparable to the Royal Festival Hall and Coventry Cathedral.
And last year a campaign to save Plymouth Hoe Centre, a former Naafi (Navy, Army and Air Forces Institutes) building constructed in the 1950s, failed when it was demolished to make way for new student accommodation.
Plymouth: 20th Century City, a National Lottery-funded website, was created in 2009 to celebrate the best of Plymouth's architecture.
Mr Thurley said he understood Plymouth had to evolve: "The last thing we're asking is for some sort of fossilised museum.
"But if the owners of the buildings and the council took more pride in them the city could be known for its unique contribution to postwar culture."
Kevin McCloud, architect and presenter of Channel Four's Grand Designs, said: "Plymouth will be all the poorer if these buildings are not conserved for future generations.
"It will be blander and more like every other faceless identikit town in Britain."