It is now almost three years since a ship the width of a football pitch and longer than the Eiffel Tower set off from Brazil bound for China.

The world’s biggest bulker — the Vale Brasil and its sisterships of 400,000 dwt — were expected to herald a new era of cheaper freight.

But the ultimate success of a bold $8bn plan to construct 35 vessels by their Brazilian mining group owner, Vale, remains an unproven gamble.