As part of his visit to Scotland, David Cameron is due to visit HMS Victorious, a Royal Navy submarine which keeps Trident nuclear missiles continuously at sea.
The Scottish National Party say they would scrap Trident in an independent Scotland.
However, Mr Cameron says it would be 'foolish' to abandon it because of the threat of nuclear attack from North Korea.
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The family of Christian Pay, who died on Friday after suspected substance abuse at a festival, have paid tribute to the Millom teenager.
The Borders Railway is to be officially opened by the Queen... on the day she becomes Britain's longest serving monarch.
Christian Pay's family say he was "loved by all" and had "the heart of a lion". The 18-year-old died after falling ill at the festival.