There have been no similar reports in the UK and the MCA said its decision was a precautionary measure.

BBC: Safety fears over herbal remedy

Matt Pavitt, from north Cornwall MCA, said there had been a rise in the number of people tombstoning across the UK in the past two years.

BBC: Tombstoning warning sign

Across the UK in the past five years there have been 18 fatalities and 57 serious injuries from tombstoning, the MCA said.

BBC: Tombstoning warning sign