Ken Livingstone said he may issue a CPO for a prominent site on Tooley Street, behind London's City Hall, due to 'unrealistic delays' in developing the site.
'It has now come to the point where I might use CPO powers for the first time on council-owned land, because we can't have sitting next to City Hall a site which has been left vacant year after year after year, when one of London's best developers has been ready to build housing on it - some for market and some for rent.'
Councillor Nick Stanton, leader of Southwark Council, said: 'I cannot believe that Ken Livingstone is suggesting he would put London taxpayers' money into a five-year court battle he has no chance of winning. We will fight all the way to protect Southwark's resources in the face of this kind of threat.
'The council is continuing to work with Berkeley Homes, and we are particularly surprised to hear these comments from Mr Livingstone considering that in recent weeks we have met and had very useful discussions with the LDA about how to move things forward,' he added.
Speaking at the launch of his draft London housing strategy yesterday, Livingstone pledged that 50,000 more affordable houses will be built in the capital over the next three years.
The Mayor also said he has no doubt Renzo Piano's Shard of Glass will be built. One of the Mayor's offices, Transport for London, will be a tenant in the skyscraper.
The tower's development has been rocked by talk of delays due to one of the three backers behind the scheme, Syrian-born billionaire Simon Halabi, being unable to come up with the funding.