FIVE protesters trying to stop an oil exploration ship leaving a port were today removed by police after a 16-hour protest, environmental group Greenpeace said.

The swoop involved some police arriving by boat and others being put on board the vessel by fork-lift truck, Greenpeace said.

The ship, the Atlantic Explorer, left port soon after the protesters were removed.

The confrontation happened in Ullapool, in the west Scotland, where six Greenpeace activists had boarded the ship in protest at oil companies turning their attention from the North Sea to the Atlantic.

As part of the same campaign, Greenpeace supporters have been occupying the isolated rock outcrop of Rockall, nearly 300 miles off the west coast of Scotland, for 23 days.

Three of the original protesters who got on to the oil exploration ships were later replaced with two new arrivals, and they locked themselves on board the ship overnight, said Greenpeace.

Two climbed the crane of the ship-which is due to carry out seismic testing in the Atlantic for oil company Conoco - and strung up a banner saying "No new oil", said a Greenpeace spokeswoman.

The protest ended when the activists were removed by police, said the spokeswoman.

Police said later four men and a woman had been arrested and charged, and a report was being submitted to the procurator fiscal at Dingwall.