Border Force officers at Gatwick Airport have found tens of thousands of dried caterpillars inside a passenger's luggage.
The discovery was made after a 22-year-old man travelling from Burkina Faso via Istanbul was stopped in the South Terminal.
When officers checked his suitcase, they found 94kg (207lb) of the dried insects shrink-wrapped in cellophane and packed into four hessian bags.
A spokesman said the man claimed they were for personal consumption and would be used as food.
The insects were seized because they breach controls on the importation of products of animal origin.
Restrictions apply to products made from meat, dairy, fish, eggs and honey, as well as some fruit, vegetables and plants.
The spokesman added: "Following the detection, which took place on 23 February, the man was warned by officers about the restrictions on bringing dried insects into the country. The insects will be destroyed."
Ingrid Smith, from Border Force, said: "This was an unusual seizure but the vigilance of our officers has stopped these dried insects from entering the UK, and possibly posing a risk to our food chain
"I would warn travellers not to attempt to bring any products of animal origin into the UK without a permit, as they may not have been inspected to appropriate standards and may contain diseases."