• Supporters say Trident fleet needed as new cold war threatens
• Critics say nuclear posture "illogical and paranoid"
• Opportunity presented by next week's nuclear summit

By Richard Norton-Taylor

Guardian Online – 20 March 2014

The idea that the Cold War would never come back has been demolished by the crisis in Ukraine, said the Tory MP, Julian Lewis. What if Putin threatened one of the Baltic States, all of which are members of NATO? Lewis, an inveterate defender of nuclear weapons, was speaking at a debate on the future of the UK's Trident nuclear missile fleet organised by the International Institute for Strategic Studies in London.

Britain needed a nuclear arsenal, with one Trident submarine continuously at sea as an "insurance policy against the unknown" and blackmail, said Lewis. Would Britain have dared to respond to the 1982 invasion of the Falklands had General Galtieri's Argentina possessed nuclear weapons?, he asked – a question which suggests that every potential aggressor should try and get their hands on nukes.

"You can never predict what's going to happen", Lord Alan West, a former head of the Navy and security minister in the last Labour government, told the IISS meeting on Tuesday.  “Some things are more important than cost", he added. Trident was the "ultimate safeguard" in an "unpredictable and chaotic world".

The former Liberal Democrat defence minister, Sir Nick Harvey, argued there was "a logic" at the time of the "balance of terror" during the (actual) Cold War when there was a need to be able to strike at a moment's notice. But there was no need now to have a nuclear sub always at sea. Britain should maintain a "nuclear capability", Harvey said, but not with a Trident submarine on patrol, 24/7.

Ah, Lewis responded, but we would not know whether the threat was imminent, and it would be too late to get a Trident sub ready in time. "Continuous at sea deterrence" or CASD, as it is called, was essential he implied. "Deterrence does not depend on uncertainty but on certainty", Lewis continued. But we were always told during the Cold War that the whole point of the UK's nuclear arsenal, alongside America's, was that it created uncertainty in the minds of a potential aggressor. It is hard to imagine the circumstances when a British prime minister would be "certain" to order a nuclear strike and make the deterrent credible.

The foreign secretary, William Hague, has described the Ukraine crisis as "the most serious test of European security in the 21st century so far". Instead of ramping up the rhetoric, world leaders could concentrate on genuine confidence-building measures at next week's Nuclear Security Summit in The Hague.

After the IISS Trident debate, Harvey told the Guardian that instead of phasing out CASD, Britain had "sustained it at gargantuan effort and expense, waving it around on the high seas, pointing at no-one in particular and for no obvious practical utility". Britain 's current posture on CASD was based on "an outdated and paranoid worldview. It is quite simply time to move down the nuclear ladder and end CASD patrols at the very least" ...