Both Culture Minister Tessa Jowell and Foreign Secretary Margaret Beckett have agreed to back the bill, which would de-list the iconic building by Robert Matthews, Johnson-Marshall and Partners.
The decision can be found in a document leaked to the Twentieth Century Society.
If this move were to go through parliament, it would certainly clear the path for the bulldozers.
The bill comes despite the building being described by many, including English Heritage (EH) a year ago, as one of the prime examples of '60s architecture in the capital.
The shock move comes just a year after Jowell herself supported an EH report that rejected an earlier bid to de-list the 1962 building.
In July 2005 she said: 'The advice from EH could not be clearer. Our experts on the historic environment believe that this is one of the most important post-war buildings of that period in London'.
The building is also praised by Pevsner as a fine example of Modernism. 'London's first major public building after the Royal Festival Hall, informal and inexpensive, and full of post-war optimism,' he wrote.
Unsurprisingly, the Twentieth Century Society is angry with the move, with director Catherine Croft warning that it could threaten the entire planning system.
'I am completely appalled by this proposal. If a bill is allowed to de-list the Commonwealth Institute then no listed building will be safe,' she said.
To object to the legislation write a letter to:
Secretary of State for Culture, Media and Sport,
Department for Culture, Media and Sport,
2 - 4 Cockspur Street,
London SW1Y 5DH