Genetically modified petunias which are being illegally sold in Britain could have ‘unexpected’ effects on gardens, and may even harm wildlife, campaigners have warned.

Defra has launched an investigation after learning that unauthorised flowering plants which are banned in the European Union are on sale in Britain.

They are working with the GM Inspectorate at the Animal & Plant Health Agency and the Horticultural Trades Association (HTA) to identify garden centres and nurseries which are selling the petunias and seeds, so that the plants can be destroyed.

Petunias are one of the most popular bedding plants in Britain, adding a swathe of colourful flowers to borders. But orange varieties including African Sunset, Pegasus Orange Morn, Pegasus Orange, Pegasus Table Orange, Potunia Plus Papay, Go!Tunia Orange, Bonnie Orange, Sanguna Patio Salmon and Sanguna Salmon were found to be genetically modified.