Thank you for contacting me about Trident.

While I appreciate your concern with this issue, I believe it is absolutely vital that we maintain a continuous independent nuclear deterrent as the ultimate guarantee of our national security. The Government has consistently set out the case for maintaining our nuclear deterrent: defence requires long-term planning and we cannot know how the international environment will change in the future.

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 greater threat. That is why I do not believe it would be right to give up this capability unilaterally.

The Government's policy is to retain the Trident continuous at sea nuclear deterrent to provide the ultimate guarantee of our safety and build the new fleet of four Successor Ballistic Missile Submarines – which in the meantime will secure thousands of highly-skilled engineering jobs in the UK.

I welcome the commitment to support the renewal of Trident with a fleet of four submarines. It would be wrong to leave Britain open to nuclear blackmail. The nuclear deterrent protects all of Britain, and scrapping it would weaken our collective defence. I fully support this position. I also believe that the replacement submarines should continue to be based on the Clyde – any alternative arrangements would significantly increase costs.

Thank you again for taking the time to contact me.