The Royal Navy has made clear that it takes security and nuclear safety extremely seriously. It is my understanding that the issue of the unauthorised release of this document and its contents were investigated fully. Having now completed the investigation, and consulted with the appropriate regulatory and operating authorities, the Defence Secretary Michael Fallon assured the House that neither the operational effectiveness of our Continuous at Sea Deterrent nor the safety of our submariners or members of the public have been compromised. The naval service has made clear that it operates its submarine fleet under the most stringent safety regime and submarines do not go to sea unless they are completely safe to do so.
On the broader issue of Trident, I believe it is absolutely vital that we maintain a continuous independent nuclear deterrent as the ultimate guarantee of our national security. We cannot rule out a major shift in the international security situation which would put us under grave threat. That is why I do not believe it would be right to give up this capability unilaterally.
I welcome the commitment that the Conservative Party will support the renewal of Trident with a fleet of four new ballistic missile submarines. It would be wrong to leave Britain open to nuclear blackmail. The nuclear deterrent protects all of Britain, and scrapping it would dangerously weaken our collective defence. I fully support this position, because this is the only sensible policy for ensuring our country has future of security.
The last Government consistently set out the case for maintaining our nuclear deterrent: although no state currently has both the intent and the capability to threaten the independence and integrity of the UK, we cannot know how the international environment will change in the future. I believe firmly that we cannot dismiss the possibility that a major direct nuclear threat to the UK might re-emerge.
Despite successes over recent decades in limiting the number of states with nuclear capabilities, we cannot rule out a major shift in the international security situation which would put us under grave threat. That is why I do not believe it would be right to give up this capability unilaterally.
The Conservatives' policy is to maintain a continuous submarine-based deterrent and to proceed with the renewal of Trident and the submarine replacement programme. Work on that programme has already begun, although final decisions on the number of replacement submarines to be ordered and the final design will be taken in 2016 at what is known as the 'Main Gate' checkpoint of the acquisition programme.