Transport for London and Catalyst Housing have been refused plans for 277 affordable homes from Harrow council.
The committee unanimously voted on 28 July to reject the Stanmore car park scheme, citing concerns over height.
The joint venture had proposed seven buildings of between six and 11 storeys and 19 three-storey townhouses. These homes would be provided as 209 shared ownership (65%) and 68 London affordable rent (35%).