Campaigning in Putney in 1978, Mrs Thatcher famously took out a pair of scissors and cut a pound note down the middle, telling her audience that the remaining stump represented what was left of the pound in your pocket after four years of Labour and high inflation.

David Cameron may soon be able to repeat the stunt — except rather than cutting a note in half he will be able to stick a bit on the end to represent the extra buying power being granted to consumers courtesy of deflation.