``The two arrested swimmers were picked up by waterborne police outside the base,'' said a spokesman at Faslane base, about 25 km (15 miles) northwest of Glasgow. ``In terms of the nuclear material, they weren't in the protected area.''

Four people were arrested overnight while attempting to cut the fence at the Royal Naval Armaments Depot at nearby Coulport, while another demonstrator was held after trying to lock himself to the front gate on Monday morning, the spokesman said.

The seven activists from England, Ireland, Belgium and the Netherlands were charged with breach of the peace and released.

The anti-nuclear group Trident Ploughshares said the arrests took the total to 93 during its two-week ``protest camp'' near Coulport against Britain's Trident submarine programme.

It says the Faslane base on Gareloch harbours submarines and the Coulport depot on Loch Long houses nuclear missiles.

``That's where the subs are, that's where the bombs are,'' Trident Ploughshares spokesman David Mackenzie said. ``Across the whole of the UK, there are about 39 sites that are related to the Trident system.''