A proposed £2bn redevelopment of King's Cross is "flawed" because it lacks affordable housing, a court has heard.
Campaigners say the project needs to be rethought
Campaigners urged the High Court to quash the plans and demolition consents granted by Camden Council.
John Hobson QC said the project was a "development of strategic importance and considerable sensitivity".
Some 1,900 homes, 20 new streets, offices, shops and restaurants are planned for 67 acres of former railway land in north London.
Claimants, the King's Cross Railway Lands Group, said councillors should be given more time to re-think the scheme.
Their counsel, Mr Hobson, told the judicial review that his clients had long campaigned for a redevelopment scheme.
But he said they felt the current project proposed by developers Argent was flawed because of inadequate affordable housing.
He said the group also opposed the razing of "key heritage buildings", such as the Stanley Building North and Culross Buildings.
Camden's development control committee gave provisional consent for the development in March 2006.
Mr Hobson said planning officers failed to inform the committee of new government guidance on the definition of affordable housing.
He said it meant the 70 units in the development previously considered to fall in the "affordable" category no longer did so.
But Timothy Corner QC, appearing for Camden, argued there was no merit in the campaigners arguments.
"We cannot see how it can possibly be said that the affordable housing in this case was anything other than compliant with (the new Government guidelines)."
The hearing is expected to finish on Friday.