Five anti-nuclear protesters blockaded a military base by chaining themselves together outside its entrance.
MoD police said protestors were arrested outside Coulport
The demonstrators turned up at the main gate of Coulport naval base in Argyll and Bute at 0700 BST on Tuesday.
They locked themselves together before lying down on the road. Ministry of Defence Police said the action caused disruption to staff and traffic.
Officers arrested the protesters - who claim to represent a protest group called The Shrubbery.
An alternative entrance to the base was opened.
Coulport is a Royal Naval Armament Depot and is situated seven miles from Faslane Naval Base, which is home to the UK's Trident nuclear weapons system.
Both bases have been subject to regular anti-nuclear protests.
A member of The Shrubbery said the action had been taken to draw attention to the pending decision to renew Trident.
The UK Government has said it faces an estimated £25bn bill to upgrade the armaments.
The Shrubbery spokesman said: "The government keeps promising a public debate on whether Trident should be replaced yet.
"This is too important to be swept out of site.
"We need to not just object politely to the idea that we should build a new generation of nuclear weapons at this point, we need to actually stop it happening."