So what can governments do to eliminate panic or turmoil in international markets? “Whatever we can”, according to Prime Minister Gordon Brown. “Not much”, according to ex-Federal Reserve chairman Alan Greenspan.

Brown and Greenspan may share many things, such as a disdain for small talk and soundbites, but listening to the two men is an illustration of the key differences between central bankers and politicians.

Brown’s presentation at Reuters today was a confident rattle through Labour economic policy in which the Prime Minister employed virtually every word and phrase of his standard vocabulary - stability, confidence, long-term commitment, flexibility, adaptability, raise our game, take no risks - to reassure his invited audience of senior business figures of his intention to manage the UK through the current international market turbulence.

Greenspan’s, however, was a softly-spoken and measured analysis of his 40 years’ experience as an economist and record four-term rule at the US Federal Reserve in which he scotched suggestions that you can do that much to eliminate turmoil.

His conclusion appeared to set him at odds with Brown’s assurances that the government would do what it could to offset the effect of turmoil.  Like it or not, he surmised, there’s little you can do about it.  So it’s impossible, then?

Greenspan warmed to his theme: troughs follow peaks as surely as night follows day. The current turmoil was an accident waiting to happen. If it hadn’t been the US sub-prime lending problems, some rupture elsewhere would have emerged to upset stability in the international financial markets.

If Brown or his Chancellor, Alistair Darling, were perturbed by this assessment of an apparent mission impossible, neither showed it. Darling was on his feet even before Greenspan had departed the podium. He thanked the ex-Federal Reserve chairman profusely for his insights and then promptly explained exactly what the UK government now plans to do to tackle the current market turbulence and its impact on consumers, savers and investors here and elsewhere.

Measures include some widely trailed changes to the Financial Services Compensation Scheme, a proposed beefing-up of banking regulations to focus on liquidity as well as solvency and a much stronger role for the IMF. He even appeared to hint that EU legislation governing how Central Banks operate as lenders of last resort might need to be clarified - perhaps to enable them to do this covertly, mused some of the audience afterwards.  

Greenspan may believe governments can’t prevent turmoil but it doesn’t look like it’s going to stop Darling and Brown trying. And if the UK government is also simultaneously going to try and amend or ‘clarify’ EU banking legislation to help them do it, it might not be the International Monetary Fund they need but the Impossible Missions Force and its key operative Mr Nathan Hunt.