But he also acknowledged that having four Vanguard-class submarines packed with nuclear warheads – with at least one kept on 24-hour patrol at any time – would do little to deter jihadis from plotting attacks against this country.
It is not here to deter terrorism; there are other policies and capabilities to deter terrorism
Rear Admiral John Weale
“This is to deter those countries that may wish to sponsor nuclear terrorism. This is a deterrent for nuclear capabilities.
“It is a deterrent for an extreme threat of a nuclear attack on her allies.”
ISIS is not thought to be close to developing or obtaining nuclear weapons, although it boasted last May that it was poised to buy its first nuclear bomb “within a year”.
Adm Weale’s comments could be viewed as a veiled warning about the threat posed by Iran and Russia’s nuclear programme.
Both countries lie within easy range of ISIS strongholds in Iraq and Syria and while Iran has no confirmed nuclear warheads at its disposal, it is widely-regarded as hoping to acquire one.
The country remains outside both the Treaty on the Non-Proliferation of Nuclear Weapons and the Comprehensive Nuclear Test Ban Treaty.
Its nuclear arsenal raises the risk that the deadly weapons or the ingredients used to construct them – enriched uranium or plutonium – could fall into the hands of ISIS.
Also speaking from Faslane, commodore Dan Martyn, the commanding officer of HMS Vigilant, insisted Britain’s stockpile of nuclear weapons was secure.
While he acknowledged “there would be a value, I would imagine, to having possession of a nuclear warhead, the security exists to make sure that doesn’t happen”.