Thousands of people have signed a petition to stop King's College London demolishing a row of Victorian buildings in central London.
The college wants to pull down the buildings on the Strand to make way for a new, bigger academic building.
But pressure group Save Britain's Heritage said the new building would be "terrifically bland".
The college said it had the support of English Heritage and Westminster Council.
A King's College London spokeswoman added: "We took all the feedback we received on our draft plans into consideration before submitting our final application.
"We are extremely proud of our heritage and are sensitive to the architecturally significant environment in which we operate at the heart of London."
By Sunday morning the petition had received 5,800 signatures.
Save Britain's Heritage, which started the petition, said the plan for 154-158 Strand, which includes a new courtyard and link to Somerset House, had received strong objections from a number of heritage campaigners.
"These are buildings of great charm on one of London's most historic and central thoroughfares: the procession route from St Paul's Cathedral to Buckingham Palace," a spokesman said.
"They are recognised as unlisted buildings of merit in the Strand Conservation Area, contributing significantly to the setting of surrounding listed buildings, including the Grade I listed Somerset House and St Mary-Le-Strand.
"The proposed design does not respect Westminster's heritage and local distinctiveness - it replaces a group of buildings with distinctive façades with something terrifically bland."
The group is calling on the college to "shelve the plans for demolition and reconsider their proposals."
Westminster Council said the plan was approved on 21 April and could not go any further within the council.
