Copper’s gain has been driven chiefly by concerns over strains on supply from key producers South America.

Researchers at the University of Michigan created a flexible transparent conductor that sandwiches a thin layer of silver between two “dielectric” materials and produces a conductive anti-reflection coating on the sheet of plastic.

Union said it would closely monitor the plans to ensure they were not used to eliminate workers during the pandemic.

It has identified a "shopping list of high-quality acquisitions" in the country, equivalent to about 28% of all areas under license.