Larry, the prime minister's kitty, has cat food that is more sustainable than the grub his owners have.
Green campaigners have revealed that the fish Larry eats has better green credentials than what is served to ministers.
In a letter written to David Cameron, the campaigners have highlighter the fact that many leading pet food producers are more committed to sourcing sustainable ingredients than the government is.
Alex Jackson, co-ordinator of the campaign, said: "It is shameful that the Government is introducing seafood standards for some parts of the public sector which are weaker than those standards in Larry's pet food."
At present, only 60 per cent of the fish bought for Whitehall and government departments purchased with taxpayers' money meets sustainability standards.
A Department for Environment, Food and Rural Affairs spokeswoman told the Press Association that the government is currently establishing the first ever government buying standards for fish and other foods.
Larry was brought into the famous Downing Street address in February following a problem with rats.