Chancellor names his preferred Budget tipple – a glass of plain London tap water
Though he has not yet ruled out accompanying it with a nip of whisky, he will avoid bottled water.
This has become the latest "green campaign", with diners encouraged to request tap water as an act of rebellion against the environmental cost of bottling and transporting mineral water.
Mr Darling's spokeswoman said he was not looking to make a big gesture. "He was asked if he would be happy to drink tap water," she said. "He said yes."
Gordon Brown, as Chancellor, shunned alcohol in favour of Highland Spring mineral water but many previous Chancellors have used the opportunity to enjoy a drink in the chamber – otherwise forbidden by parliamentary rules.
Kenneth Clarke drank Glenfarclas whisky, while Norman Lamont opted for Highland Park. Before them Geoffrey Howe had a gin and tonic, Benjamin Disraeli drank brandy and water and William Gladstone mixed sherry with beaten egg.
Labour MP Graham Stringer, who submitted a motion calling for the Commons authorities to stop buying 250,000 bottles of water a year, said: "I think a glass of water would be perfectly good for the Chancellor."