Updated March 12, 2009

Buckingham Palace, the main residence of British sovereigns for almost 175 years, leaks so much energy it could be a sieve. That's the upshot of news reports from London detailing results of an energy survey of 170 buildings.

Thermal imaging of the 775-room palace showed heat flowing from closed, curtained windows, pouring from the roof and streaming through cracks in the walls, according to the Telegraph, the Daily Express and other news organizations.

Buckingham Palace
Renewable energy firm Navitron helped conduct the survey that also found St. James' Palace — which is adjacent to Clarence House, the official London residence of the Prince of Wales — to be another energy offender. It took 12th place on a list of the dozen least green buildings, according to the Telegraph.

Other energy inefficient buildings include the Department of Environment, which took second place, the Treasury, the Ministry of Defence and Portcullis House, which opened in 2001 and contains the offices for about a third of the Members of Parliament. The Daily Express reported that the Home Office and the headquarters of MI6 are also on the list.

Then on Thursday, the Daily Mail weighed in with the entire roster of the "Dirty Dozen" as the stir over the energy survey and its results continued:

1. Buckingham Palace
2. DECC (Defra) [The Department of Energy and Climate Change (Department for Environment, Food and Rural Affairs)]
3. Ministry of Defence
4. Horse Guards Barracks
5. Shell Building
6. Home Office
7. Houses of Parliament
8. Treasury
9. Portcullis House
10. MI6 HQ
11. Albert Hall
12. St James' Palace

The HSBC Tower complex at Canary Wharf was named the most energy efficient building surveyed.
The Hong Kong and Shanghai Banking Corporation tower block in Canary Wharf was named the most energy efficient building, according to news reports.

Balmoral, the royal family's retreat in Scotland, is to become the first energy self-sufficient property among the royal estates. However at Buckingham Palace, where the queen is said to have established an energy saving committee, energy bills tallied some 2.2 millions pounds (an estimated $3 million) in 2008.

Reports of the survey emerged as Prince Charles traveled in South America to advance environmental advocacy. He scheduled to make a major speech on climate change in Brazil on Thursday.