Mr Marr told Mr Brown he wanted to ask about “something everybody has been talking about in the Westminster village… A lot of people in this country use prescription painkillers and pills to help them get through. Are you one of them?”
The prime minister replied: “No. I think this is the sort of questioning which is all too often entering the lexicon of British politics.”
He also denied his sight is deteriorating – something he was asked about last week on US television.
The prime minister lost the sight in one eye following a teenage rugby accident and suffers reduced vision in the other eye – but he said he had recently undergone an annual check-up which showed no deterioration in the vision of his good eye.
When Andrew Marr asked again about the issue of painkiller use, the prime minister said: “I’ve already answered that question.”