A Canadian deep-sea mining firm has revealed it has been negotiating with the Trump administration to bypass a UN treaty and potentially gain authorisation from the US to mine in international waters.

The revelation has stunned environmentalists, who condemned the move as “reckless” and a “slap in the face for multilateralism”.

In a statement on its website on Thursday, Gerard Barron, chief executive of The Metals Company (TMC), said: “We believe we have sufficient knowledge to get started and prove we can manage environmental risks.

“What we need is a regulator with a robust regulatory regime, and who is willing to give our application a fair hearing. That’s why we’ve formally initiated the process of applying for licences and permits under the existing US seabed mining code.”