The violence, when it came yesterday, was as sickening as it was predictable. Such was the array of different protest groups ranged against the G20 conference in London — everyone from anarchists and anti-war groups to artists and intellectuals — that disorder on some scale was almost inevitable.

The sight of hundreds of protestors pelting police with paint bombs, eggs and beer cans was nonetheless shocking — all the more incongruous for taking place against the backdrop of the Bank of England's neoclassical pile in Threadneedle Street.

Even before the violence — masked anarchists also smashed up a branch of the Royal Bank of Scotland in the City — the paucity of fresh thinking amid all the rhetoric was dismaying.

The fine anti-globalisation sloganeering of many of the protestors seemed far removed from the economic reality staring workers at Visteon and FG Wilson in the face, for example.

It would be less-dispiriting if the leaders of the G20

— who between them represent 85 per cent of the world's economy — could demonstrate a more joined-up approach. But not only will G20 not provide the panacea to the global economic crisis, it cannot. In that respect, the heads of state and the protestors have more in common than they realise.

For the reality is that the Europeans had already effectively wrecked any hope the London summit had of approving an immediate financial stimulus.

France's Nicolas Sarkozy and Angela Merkel of Germany, in particular, are resisting US calls to promise to spend more not only this year, but in 2010.

Gordon Brown and Barack Obama — for all their talk of reflating the world economy — are both running huge current and budget deficits which will prevent them realising their global ambitions unaided. While Brown is surely right to call for intervention to make the markets fairer and more “ethical”, David Cameron will be quick to refresh the public's memory of the former chancellor's laissez-faire record while in Number 11.

Obama, meanwhile, is equally correct when he says that only massive spending by European and Far Eastern economies can avoid recession slip-slid

ing into depression. But the idea of taking a lecture in economic probity from the country that gave the world ‘toxic’ mortgages is probably as appealing as listening to Sir Fred Goodwin discourse on the nature of humility.

Even with all sides playing down expectations of a comprehensive agreement in recent days, the prospects of more than a curate's egg are slim.

Northern Ireland's own painful experience of the past 30 years shows that street violence is the road to nowhere. The Assembly, for its stuttering part, has taught our MLAs another sobering lesson: catcall politics may pass muster in opposition; they are left pitifully exposed in Government.

None of which is of any consolation whatsoever to the hundreds of Northern Ireland workers who this week heard the factory gates clang behind them for the last time.

Protest — like the poor of St Paul — will always be with us. What the present situation demands is an altogether scarcer commodity: leadership.