Scrapping Britain 's Trident nuclear deterrent is a key SNP policy . The UK government has said it will not renew the contract for its existing fleet of four Vanguard submarines, which are due to be decommissioned in 2023 and replaced by new generation boats that can carry more Nicola Sturgeon has revealed SNP could still prop up the Labour Party . Labour MPs are urging Ed Miliband to rule out a deal with the SNP . Latest polls suggest the SNP could win up to 56 of Scotland 's 59 seats .
Scrapping Britain 's Trident nuclear deterrent is a key SNP policy . Ed Miliband has insisted Labour will not compromise over Trident renewal . Nicola Sturgeon has revealed SNP could still prop up the Labour Party . Labour MPs are urging Ed Miliband to rule out a deal with the SNP . Latest polls suggest the SNP could win up to 56 of Scotland 's 59 seats .