Former environment minister Lord Zac Goldsmith and Green party MP Caroline Lucas are among at least 22 members of the Conservative, Labour, Liberal Democrat, Green and Scottish National parties calling on Rishi Sunak to back a moratorium on mining in international waters.

The UK government sponsors two exploration contracts across 133,539 square kilometres in the Pacific Ocean between Hawaii and Mexico for small lumps that sit on the seafloor and contain nickel, copper and cobalt. It has invested £6mn through the Natural Environment Research Council, according to the Natural History Museum, in a four-year research project involving trips to the area by scientists.