The United Kingdom's National Crime Agency (NCA) has warned travellers from Thailand that any attempt to bring cannabis into the UK could result in their arrest.

In addition to Thailand, the warning includes travellers from Canada and the United States and follows a huge increase in reported arrests.

According to the British embassy in Bangkok, 378 air passengers have been taken into custody for smuggling cannabis, and an estimated 15 tonnes of the drug has been detected and seized at UK airports so far this year. The amount is around three times higher than in 2023 when about five tonnes of cannabis was seized and 136 people arrested.

Of all the arrests this year, 184 cases were reported with cannabis originating from Thailand, with 75 related to cannabis from Canada and 47 to cannabis from the US. The drug is legal to varying degrees in all three jurisdictions.

People travelling with narcotics as couriers into the UK can face up to 14 years in prison, the NCA said.

This year, 196 people have already been convicted and given sentences totalling almost 188 years.

NCA experts say the trend is being fuelled by organised criminal gangs who have access to cannabis grown overseas in locations where it is legal and recruit couriers to transport the drug to the UK. The NCA continues to work with partners in the UK and overseas to target high-risk routes.