International environmental groups are warning Britain's government not to reduce its commitment to fighting climate change and wildlife poaching when it negotiates post-Brexit trade arrangements with other countries.

Greenpeace, WWF, and Friends of the Earth have signed a letter to Prime Minister Theresa May stressing that environmental protection must remain a priority after Britain leaves the European Union.

They were joined by tennis star Andy Murray and singer Will Young.

The letter released Sunday expresses alarm at newspaper reports that Britain's environmental commitments would be watered down in the post-Brexit era as the country pursues lucrative trade deals.

It calls for Britain to deliver on its promises for environmental protection.