Councillors gave the green light to the project yesterday - the largest regeneration scheme seen in the capital for 100 years - at a dramatic late-night planning committee hearing.
Campaigners at the meeting threatened to derail the project - which includes 450,000 sq m of offices and 2,000 homes - at the last moment by again attempting to highlight perceived 'failings'.
They criticised the masterplan - by Allies and Morrison and Dimitri Porphyrios - for its mix of housing and lack of school provision.
But the scheme was passed at the last minute, before councillors would have been forced to adjourn at 10.45pm.
Explaining his scheme's benefits, Argent chief executive Roger Madelin said: 'Can you imagine not having to buy Time Out magazine again? You just turn up at King's Cross.'
After the decision, Camden Council leader Raj Chada said: 'The redevelopment will recognise and protect King's Cross' valuable architectural heritage while creating a sustainable and attractive future environment.'