Cracks are visible on some of the chimneys and need to be rebuilt for safety reasons and to ensure they last, say the developers.
But campaigners say taking the chimneys down will ruin the character of the building.
A small group of people dressed as monkeys gathered outside the station today with placards claiming the company behind the development 'don't give two monkeys' for the iconic building.
More top news
Dean Waite's prints of London icons are made with little more than a biro.
Ahead of tonight's planned strike, London Underground have offered new payments and terms to staff to avert the strike.
The capital's theatres also generate more searches than those in any other city, according to research by Google.