The BBC is facing a new controversy over doctored footage - after admitting to changing the sequence of events in a documentary about the Prime Minister.

In a 12-minute film for the corporation's flagship Newsnight programme, journalist Jamie Campbell attempted to secure an interview with Gordon Brown as he toured the country before moving into 10 Downing Street.

The documentary, which was broadcast on June 26, first showed Campbell clashing with Mr Brown's press officer, Balshen Izzet. Later on in the film, Campbell was seen in a confrontation with police when making another attempt to speak to Brown. He suggested that Ms. Izzet had called them in retaliation for the earlier incident. However, the two incidents had happened weeks apart and in reverse order. Furthermore, policemen had decided to speak to Campbell on their own accord for security reasons.

The PM's officials are said to have described the film, which accused Brown of being "heavy-handed" in his attempts to avoid questioning, as "unfair, unbalanced, unnecessarily personal, and disingenuous".

A source close to Brown told the Mail on Sunday: "Newsnight doctored the film to make it appear as though the Press officer called the police because Mr Campbell had clashed with her earlier that night. It is totally untrue. The events happened two weeks apart and in a different order. Newsnight changed it to make it more damaging. Ms Izzet did not call the police as Mr Campbell alleged."

A spokeswoman for the BBC said: "We have acknowledged that the sequences in the film were not shown in chronological order. There was no intention to deceive anybody. The commentary does not suggest that the two are chronological and that one led to the other. The sequences would have had the same meaning if we had run them in the reverse order."

The corporation recently apologised for releasing misleading footage of the Queen in a trailer for a new documentary.