THE virus-hit Southampton based cruise liner Aurora was homeward bound today after leaving Gibraltar and a political storm in Anglo-Spanish relations.

The P&O luxury ship is due back in the city on Thursday, complete with its 1,800 passengers, 500 of who were struck down by a highly contagious bug.

But the health scare turned political yesterday when Madrid closed its border with Gibraltar after the liner docked in the British colony.

The move, the first of its kind in more than 30 years, sparked angry criticism from senior British and Gibraltarian politicians, who labelled it "unnecessary and disproportionate".

The frontier was eventually reopened last night, three hours after the Aurora had left for its final leg of a 17-day cruise.

The Foreign Office welcomed the reopening but a spokesman stressed: "The Foreign Secretary did not believe it should have been closed in the first place."

Jack Straw told reporters: "I regret the action taken by the Spanish government, which is unnecessary and disproportionate."

Gibraltar's Chief Minister Peter Caruana, pictured, said the British passengers on board had been forced to "float around the Mediterranean like unwanted refugees".

He called the closure "knee-jerk" and "unacceptable interference by Spain".

Problems first hit the Aurora after more than 500 of its British passengers contracted the contagious norovirus which causes nausea, chronic diarrhoea and vomiting.

They were only allowed off the ship in Gibraltar yesterday morning after it was refused permission to dock in Greece.

A P&O Cruises spokesman said yesterday just six passengers were still displaying symptoms of the bug, although Gibraltar's authorities had asked 50 to remain on board the cruise liner while it docked there.

A lawyer representing some passengers said he was aware of an outbreak on the ship earlier this year and would be seeking compensation for them.