Gorst won planning for the residential scheme in Hampstead in January 2006, with a proposal to replace an existing 1951 house which is located on privately owned Metropolitan Open Land (MOL).
However, the scheme was met with fierce opposition from the Heath and Hampstead Society, backed by former RIBA president Marco Goldschmied and Baron Cohen.
In April last year, campaigners won the first round when the High Court ruled against the scheme (AJ 05.04.07), prompting Gorst to say at the time: ‘This ruling strips all local authorities of the responsibilities or powers to decide any development on its individual merits. It will have massive repercussions.
'Our scheme was mathematically larger but the volume of it was nowhere near the numbers they were claiming. Besides most of the extra volume was to the rear of the building, using up dark, dank, hidden space.'
Gorst was not available to comment on the latest, and final ruling.