Harman said she meant to say Blair and Brown were a good team

The slip came as Ms Harman spoke on BBC One's Question Time about the Budget.

She began her answer: "Since Gordon Brown became prime minister..." before hiding her face amid hysterical laughter from her fellow panellists.

The minister explained: "I was just thinking about the prime minister and the chancellor at the same time and I conflated it."

Ms Harman, who is the solicitor general, added: "I was going to say that he and the prime minister have been a hugely important and successful team running the country and the economy."

Her gaffe caused huge applause and whoops from the studio audience, with presenter David Dimbleby joking: "The Freudian slip shows where your heart really lies, doesn't it?"