PHILIP Hammond, the 57-year-old multimillionaire who is Defence Secretary in the Coalition Government, is one of these astute but annoying politicians who have a reputation for being quietly effective.

You don't hear much from them and for that reason they are not always scrutinised as they should be. In the lists of those who might be poised to succeed David Cameron, Mr Hammond is always there or thereabouts, lurking a little behind the more brash Boris Johnson

Suddenly, and uncharacteristically, Mr Hammond broke rank at the end of last week. He bluntly stated that any further defence cuts would be "impossible".

Fair enough; he was protecting his department, though in saying the first priority had to be defending the UK "and maintaining law and order" he seemed to be, rather ominously, usurping the role of the police.

The meat came in Mr Hammond's further assertion that welfare spending should be falling and that cuts should be made in welfare, not defence. It was fine to protect his department; it was far more controversial to tell another minister that he should be making the cuts.

His uncharacteristically dramatic intervention could be seen as a direct attack on the LibDems in the Coalition. LibDems believe that welfare spending should be ring-fenced. I'm not sure about that; the welfare budget is colossal and a few judicious cuts could be made without in any way harming the vulnerable or the dependent. But, and very ironically, an area where more rather than less welfare spending is needed is in the "aftercare" of troops who leave the armed forces. A worrying number of them end up in prison.

Vince Cable was quick to lead the LibDem fightback against Mr Hammond's carefully calculated outburst. The Business Secretary pointed out that all the savings required, and more, could be made by getting rid of Trident.

This is such a straightforward and well-made point that more of Mr Cable's colleagues should be making it, day in, day out. Our so-called nuclear deterrent is not deterring anyone or any regime. The real threat to our national security, and it is a growing threat, comes from terrorism, cyber attacks and the like. Trident is an antique system, a throwback to the days of the Cold War when it certainly could be justified strategically.

Sadly, I think the reason that some UK politicians are so keen to cling on to these redundant and vastly expensive weapons of mass destruction is that they reckon they give the UK a place at the so-called international top table. I would not want to sit at any top table because I possess the means to obliterate hundreds of thousands of human beings. But for our more deluded leaders, our permanent membership of the UK Security Council, in particular, is a badge of world status. They can't stand the thought of losing it.

The UK is not a power of world significance. It is a declining state on the fringe of a declining continent and, like so many countries in this failing continent, it is grappling with acute and almost insoluble financial problems. Grandstanding on the international stage is the last thing we should be doing. Our interventions in the likes of Iraq and Afghanistan have been bloody and counterproductive.

Meanwhile there is, if only the likes of Messrs Cameron and Hammond would grasp it, another good reason for getting rid of Trident. This would, at a stroke, remove one of the most difficult and problematic issues for them in the upcoming referendum on Scottish independence. These weapons are based in Scotland and the Scottish Government does not want them.

Neither, I'm pretty certain, do the Scottish people. If Mr Cameron were big enough to announce that he was going to abandon Trident, he would at a stroke be making huge potential savings and also removing what many Scots rightly regard as an affront, and a very dangerous one at that. And that could significantly alter the terrain on which the coming referendum will be fought.