The Scottish National Party, which could play a key role in British politics following elections in May, called on the main political parties to scrap Britain's nuclear deterrent on Tuesday.

The SNP's leader in parliament, Angus Robertson, told MPs that the Trident nuclear-armed submarines, which are currently at the Faslane base near Glasgow in Scotland, should not be replaced.

"The time has come to put down a marker about scrapping Trident and not replacing these weapons of mass destruction," Robertson told parliament.

The SNP, which campaigns for Scottish independence from the United Kingdom, is often mentioned as holding a possible "kingmaker" role after the next election in coalition with the Labour party.

The government and opposition Labour have both committed to Trident, although some Labour MPs have rebelled against the party line.

"With polls showing we may very well hold the balance of power after the next general election we will do everything we can to ensure that Trident replacement does not go ahead," Robertson said.

He estimated that the savings from scrapping Trident could add up to 100 billion pounds (131 billion euros, $151 billion).

The SNP currently has only six lawmakers in parliament, but that number is expected to at least double at the general election.

Britain's nuclear-armed status has underpinned its standing as a diplomatic power for decades.

Under a deal sealed at the height of the Cold War, the United States supplies Britain with nuclear missiles.

There are four submarines in the Trident fleet, at least one of which is on patrol somewhere in the world 24 hours a day.