London - Nigella Lawson was banned from boarding a flight to the US because of her previous confession to taking drugs.
The glamorous chef - who admitted during the fraud trial of her former employees last year that she had taken cocaine and smoked marijuana - was travelling alone on Sunday and had cleared check in and security at London's Heathrow airport but was then told she couldn't get on the plane to Los Angeles.
A source told the Daily Mail newspaper: "She didn't seem to say much, but she did not look happy. She could not get on the flight so she had to turn around and leave."
The 54-year-old star was forced to return to the first class check-in to collect her luggage.
It is thought US authorities had warned British Airways staff not to allow her to travel to California, as she would have been refused entry.
The country ask travellers if they have ever been arrested or convicted on drugs charges, and can prevent entry even if no charges were brought following an admission of using illegal substances.
Though the US Department of Homeland Security said it did not comment on individual cases, a spokesperson said those who had admitted committing drugs offences could be deemed "inadmissible" and would have to go through a lengthy process to be allowed back into the country.
He said: "In general, an alien found inadmissible will need a waiver of inadmissibility. Depending on the basis of their refusal they may be eligible to apply in advance of travel for a temporary waiver of inadmissibility. The waiver application process can be lengthy."
Nigella is expected to seek legal advice to help her get back into the US, which she visits regularly for both holidays and her work on 'The Taste'.
A spokesman for the star said only: "We would never comment on Nigella's travel plans." - Bang Showbiz