Chris Upton reflects on the voyage that turned George Anson into a military hero.

In September 1740 George Anson, once of Staffordshire, now of the high seas, set forth on one of the most dramatic voyages in British naval history.

Anson and his squadron of six warships were despatched across the Atlantic to harry and loot Spanish ships, and undermine, once and for all, that nation’s dominance of the Americas.

“You should then return home,” said his instructions, “either by way of China or by Cape Horn as you think best.”

On board were almost 2,000 men. To round Cape Horn at any time was dangerous enough, but in mid-winter it was positively suicidal. The mainmast of one of the vessels – the Tryal – was snapped, while another of the fleet was separated from the squadron for almost a month. Two of the ships’ captains were buried at sea before any Spanish ship was even sighted.

For those left on board, however, there was plenty to distract them from the raging seas. Scurvy had broken out by the time they were in mid-Atlantic, and wherever they landed, malaria could be added to the menu. Of the mariners on the Tryal, less than half survived, and less than a quarter of the sailors on the Gloucester came through.

Two more of the ships turned back, unable to round the Cape, and reported back home in England that Anson’s vessel – the Centurion – had probably gone down.

The one scant consolation was that the Spanish fleet, pursuing the intruders around the Cape, had suffered even heavier losses. Anson, however, was not dead. With their fresh water almost exhausted, the remaining ships had put into Juan Fernandez.

Here, on the island made famous by Robinson Crusoe, the men recovered and the ships were repaired. It was September 1741 – a year since they had first set sail – and there were now just three of the squadron left.

But now at last, refreshed and rejuvenated, Anson could begin to do what he was sent to perform in the first place: to capture Spanish ships and raid their ports.

Three Spanish ships, one heavy with silver, were seized before November was out, and the coastal town of Paita raided and burnt.

The capture of enemy ships allowed Anson to replenish his fleet, which was timely, for the Gloucester was shipping water, and its crew cut down by scurvy to just 90 of the original 400. Only by sinking the Gloucester and combining the crews on the Centurion, was there sufficient manpower to continue.

There was, however, one last Spanish vessel to engage, the seizing of which would turn one of the greatest British naval disasters of all time into one labelled “mission accomplished”.

The prize was a treasure galleon which made a regular journey between Acapulco and Manila. Capture this, Anson told his weary crew, and they could all go home.