Boris Johnson was caught out by Alex Salmond of not having even read a study he used to make the case for Brexit.
Speaking at the EU referendum debate hosted by The Daily Telegraph/Huffington Post/YouTube on Tuesday evening, the former mayor of London said immigration had a "compression effect" on wages.
"A Bank of England study that showed that for every 10% increase in immigration there was a 2% reduction in wages, he said.
But Salmond cut in: "No it didn't, have you read that study, Boris? Have you actually read it?"
Boris admitted to laughter from the audience: "I have not read that study."
Salmond accused Boris of trying to "scaremonger on wages" during the referendum campaign.