Trident: What the parties plan on renewal

The renewal of the Trident nuclear submarine fleet has long been a divisive political issue, here is a look at what the main parties believe the future of Trident should be.

• Labour is committed to replacing the UK's ageing fleet of Vanguard submarines which carry Trident nuclear missiles, but would consider reducing the number to three if a continuous deterrent could be maintained.
• Conservatives will pledge to renew all four submarines, Michael Fallon said.
• Liberal Democrats have said they would retain Trident but say two submarines would provide a "perfectly meaningful deterrent", while three would enable the UK to have a "continuous at-sea deterrence", Sir Nick Harvey said.
• Ukip would commit to "totally upgrading Trident" Patrick O'Flynn said.

• Both the SNP and Green party are opposed to renewing Trident.