The rain had a lot to do with it apparently. One reason the Ministry of Defence was so keen on situating nuclear submarines in Loch Long is that it rains there 260 days a year. Any nuclear spillage would, therefore, be washed away rapidly into the deep waters of the Firth of Clyde. A reassuring thought, for today's SNP-led Trident Summit in Glasgow on how to wash nuclear weapons out of Scotland.

A forlorn hope, you say. Nuclear weapons have been located in the Clyde since the sixties - get over it. However, there has never been any serious attempt to use public policy to challenge Trident until now. Alex Salmond is planning to pit the agencies of the state against the defence of the realm.

Salmond is too clever to go in for empty gestures such as declaring nuclear free zones, as Labour-led councils did back in the 1980s. Nor is he going to send the police to arrest for war crimes civil servants or public employees who are involved in the nuclear establishment, though the idea has been talked about.

No, the Nationalists intend to use a combination of moral "suasion" and public policy to frustrate Trident, in the hope that the MoD will eventually decide that locating nuclear weapons on the Clyde is just too much hassle. If England wants them, it can have them.

First, the moral bit. There has been outrage in the Scotland Office at the SNP leader's call for Scotland to have observer status at next year's Nuclear Non-Proliferation Treaty (NNPT) talks. It was reported in yesterday's press as "Salmond demanding a seat at the UN", which is not the case. A seat at the United Nations might be nice, but Scotland isn't actually an independent nation and so wouldn't be eligible. However, there is nothing to stop the 189 signatories to the NNPT inviting Scotland to attend on advisory basis.

It's actually very difficult to argue a coherent case against Scotland having a presence at international disarmament talks, since Scotland has had the dubious honour of hosting Britain's nuclear deterrent for 40 years. In June, a majority of MSPs in the Scottish Parliament voted against Trident renewal, as did a majority of Scottish MPs in Westminster in March.

But David Cairns, the Scotland Office minister, says that Alex Salmond should be sorting out the free personal care instead of "cavorting across the world stage with his discredited loony-left policies" and giving comfort to our enemies. Well, they are also his loony policies, since Labour is still formally committed to pursuing "multilateral nuclear disarmament" under a defence policy which dates from the late 1980s.

If he is saying that the presence of an anti-nuclear Scottish Government representative at the NNPT talks might be an embarrassment, then fair enough. But Britain has every cause to be embarrassed, since we've driven a coach and horses through the NNPT by renewing the Trident missile system. Article VI of the NNPT requires signatory nations to work toward "cessation of the nuclear arms race at an early date and to nuclear disarmament". The government insists that developing a new generation of Trident does not run counter to this commitment, but many disagree, including Matrix Chambers, Cherie Blair's own law firm.

Possession of strategic nuclear weapons certainly is against the spirit, if not the letter, of international law, because they are the ultimate terror weapons, designed to cause maximum indiscriminate loss of civilian life. These devices have been around for so long in Scottish waters that we tend to forget they are weapons of mass destruction designed to destroy not Islamic terrorists, but large cities. Each Trident missile has a range of more than 4600 miles and carries a punch equivalent to eight Hiroshimas. Britain deploys 16 of these on each of our four Vanguard-class submarines.

Of course, defence is a reserved issue and Holyrood has no formal powers over nuclear weapons. However, the Scottish Parliament can take an interest under any number of headings, from health and safety to planning, transport to the environment. The key is to use these powers intelligently and not just to cause naive mischief. This is exactly what the Scottish Government intends to do.

The upgrading of the facilities on the Clyde for the new Trident system will require planning permission. This will require Scottish ministerial approval and could fall foul of pollution controls administered by the Scottish Environment Protection Agency. Earlier this month, the Sunday Herald revealed that Sepa had already been in contact with the MoD over problems with Trident developments at Faslane and Coulport.

Nuclear defence establishments are not subject to the laws on health and safety, but that could change. However, perhaps the most likely source of pressure would be over the transport of nuclear weapons from the Atomic Weapons Establishment in Berkshire, to the depot at HMNB Coulport. Life could become very difficult if the Scottish Government decided to apply rigorous safety standards to the heavily-armed convoys that schlep up to Loch Long up to six times every year.

In July, under the Freedom of Information Act, the MoD was forced to reveal that there had been 67 safety incidents during convoys in the past seven years alone.

These ranged from brake failure and roadside fires, to nine separate incidents involving delays by anti-nuclear campaigners. In 2004, the convoy was delayed 16 minutes by a protest at Balloch on Loch Lomond.

Of course, the weapons are not armed, like those nuclear bombs flown unwittingly across the US recently by B52s. But it still looks like an accident waiting to happen. If I were an Islamist terrorist wanting to make a point, I know where I would be standing with my suicide bombs.

Now, it was reported before the Scottish election in May that the MoD was actively looking at alternative bases for Trident in England in the event of an SNP government taking over.

It looked at Devonport on the south coast where the four Vanguard submarines are refitted and refuelled. Relocating Trident there would be very, very difficult because of the lack of space, the lack of deep water and the fact that the submarines would be sailing in and out of one of the most crowded shipping lanes in the world.

There's not a lot of rain there either. The MoD doesn't regard relocation of the nuclear deterrent south as a serious option. But if the roads north were blocked, they might just have to find somewhere else - at least that's what the Scottish Government believes. And, make no mistake, it is serious.