The 30-year-old royal - who has been suffering from acute morning sickness throughout her pregnancy, which was announced earlier this month - has been inundated with boxes of the calorific treats, which are a traditional anti-sickness cure.

A source told The Sun on Sunday newspaper: "A lot of women develop cravings during pregnancy and Kate is no exception. She has got a real taste for these biscuits.

"Lavender is said to have healing properties, so it is not such a wacky food to nibble on when you're pregnant."

The royal family have been sending Catherine - who was known as Kate Middleton prior to her and Prince William's nuptials last year - boxes of the sugary snacks, which are sold by her father-in-law Prince Charles' Duchy Originals organic food brand and London-based department store Fortnum & Mason.

Earlier this month, the Duchess of Cambridge - who spent four days at the King Edward VII Hospital in London, where she was being treated for acute morning sickness - was said to be craving papaya fruit.

Her former school friend Jessica Hay explained: "[Kate] particularly wants papaya fruit and they're busy making plans for Christmas. She's already feeling much better and, as they do with everything, they're getting through the ordeal by making each other laugh."