Nigella Lawson may be forced to take a blood test before being allowed to travel to the US.

The glamorous chef was banned from boarding a flight to Los Angeles on Sunday (30.03.14) because of her previous confession to taking drugs at a court trial earlier this year.

However, the brunette beauty will to prove she's clear of illegal substances before being allowed into the US.

Leading immigration lawyer Charlotte Slocombe told The Sun newspaper: ''It will be the physician's job to determine whether or not she's a drug abuser.

''This includes an interview process and a possible blood sample. As long as the physician is certain that it's over a year since she took drugs, then she may get a visa.

''In theory, following the letter of the law, she could be inadmissible for a visa, full stop. It's complex.''

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.

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'.