For generations, the reason why the Mary Rose sank during a battle with a French invasion force has divided historians.

Now a new theory can be added to the list of suggestions about why the pride of Henry VIII's navy was lost: two thirds of its crew were foreigners who failed to understand orders.

Forensic science examinations of the 16th-century crew's skulls have revealed that the majority were not British but southern European, most probably Spanish.

Researchers believe that the vessel's fate was sealed because of their inability to understand their officers' orders when it began taking on water in the Solent, off Portsmouth, in 1545.

It is believed that the crewmen were either mercenaries from the Continent recruited to fight by Henry VIII or Spanish soldiers shipwrecked penniless in Britain and forced into military service.

The new theory also goes some way towards solving the riddle of the last words reputedly shouted by the ship's admiral, George Carew, to another English ship, that his men were “knaves I cannot rule”. The latest explanation has been put forward by Hugh Montgomery, a medical researcher at University College London.

Until now, it had always been believed that the Mary Rose sank as it performed a sharp turn, causing the open gun ports to submerge, flooding the vessel.

However, Professor Montgomery claims that the ports were left open only because the Spanish crewmen could not understand quickly enough the command to close them.