Warning of stowaway snakes and tree-frogs hiding in pot plants

“Adult snakes and lizards are just the tip of the iceberg,” said Prof William Sutherland, of the University of Cambridge. “If they’re getting through, what’s the chance of us spotting small insects and fungi – the things that really cause the problems?”

The production of ornamental plants is growing fast and expanding geographically, particularly in East Africa and South America.

While regulations and border checks are in place, the sheer volume of cut flowers and ornamental plants being traded at speed makes it extremely difficult to intercept all the pests and diseases they carry, said Dr Silviu Petrovan of the University of Cambridge.

“Even with the best of intentions, unwanted hitchhikers are getting through customs import checks all the time,” he said.