Jam-making enthusiast and allotment aficionado Jeremy Corbyn is "totally anti-sugar", the Labour leader revealed today (19 September). The left-winger was taking part in an online hustings on MumsNet when he dropped the snack-related bombshell.

Asked to name his favourite type of biscuit, he said: "I'm totally anti-sugar on health grounds, so eat very few biscuits, but if forced to accept one, it's always a pleasure to have a shortbread."

But social media users were quick to point out that one of his favourite past times, making jam, involves using the sweet preservative.

The MumsNet biscuit question has become a political rite of passage, with former Labour Prime Minister Gordon Brown causing a very minor controversy by apparently dodging the question in 2009. He later admitted to indulging in "anything with a bit of chocolate on it".

Then Conservative leader David Cameron, meanwhile, told the forums he likes oatcakes "with butter and cheese".

More recently Labour leadership challenger Owen Smith declared in August that he was "BIG on biscuits." He added: "Custard creams a definite favourite, but round my nan's as a boy I used to like a Garibaldi. You've got to like a biccy named after a revolutionary."

Key dates of the Labour leadership election

  • 18 July: Signing up as a registered supporter to vote in the election begins.
  • 19 - 20 July: Number of MP nominations for each candidate to be published.
  • 20 July: Deadline for people to sign up as a registered supporter closes.
  • 22 August: Ballot papers will begin to be sent out around the UK, but to Labour Party members only.
  • 21 September: Deadline for ballot papers to be returned is midday.
  • 24 September: The election result will be announced at a Leadership Conference in Liverpool.