BRITAIN'S Conservative Prime Minister, David Cameron, has personally congratulated Julia Gillard on her carbon tax policy in a letter penned from the desk of 10 Downing Street.

In a clear embarrassment to the Opposition Leader, Tony Abbott, and his Coalition - who have vehemently opposed any price on carbon - Mr Cameron described the federal Labor government's move on climate change as "bold" and "ambitious".

Distraction for Coalition ... David Cameron and Julia Gillard are in agreement. Credit:Reuters

Mr Cameron said he was convinced climate change was one of the "most pressing threats to [a nation's] prosperity and security".

"I have always been clear that in order to tackle it [climate change] effectively, all major economies will need to take robust action to curb their emissions and put their economies on a more sustainable, low-carbon footing," he said.