Just a few months ago, the best-known base metal was looking like the least loved. Copper, first mined 10,000 years ago and used extensively in construction and electrical applications, tumbled 10 per cent in the first quarter of the year to $6,430 a tonne, and hit its lowest level since 2010.

The fall was sparked by events in China, which consumes more than 40 per cent of the world copper supply. The country’s first domestic bond default raised fears about the economy and the possible unwinding of financing deals that used copper as collateral. With a surge in mine production anticipated this year, further price falls seemed possible. Thomson Reuters GFMS, a metals research firm, said in its annual industry survey in April that copper could test $6,000 a tonne this year. Goldman Sachs forecast a year-end price of $6,200 a tonne.

That seems a long way away. Despite a blip in June, because of worries about an alleged metals fraud in the Chinese port of Qingdao, copper has rebounded 8 per cent since March. Yesterday -afternoon, at $7,140 a tonne for three month delivery on the London Metal Exchange, it was down just 3 per cent for the year.