David Prosser: G20 bonus deal already looks strained

Outlook Lord Myners hasn't always "got" the issues at stake in the debate over City pay, failing to spot the incendiary nature of Sir Fred Goodwin's pension boost at Royal Bank of Scotland last year. But the urgency with which he is now tackling City bonuses, yesterday summoning representatives of international banks for a summit on pay, suggests he has wised up.

The problem for the Treasury is that its power on bonuses has limits. It has already persuaded British banks to sign up early to the G20 agreement on bonuses and, after yesterday, now many foreign banks with a London presence will join them. But the Financial Services Authority, whose pay code reflects the G20 settlement, is not the primary regulator for all of these institutions.

Even if Lord Myners can get every bank operating in London to respect the G20 principles, banking is an international activity. The agreement signed in Pittsburgh was supposed to reflect that, with nations around the world bringing their banks into line in order to prevent certain financial centres getting a competitive edge.

This deal already seems to be unravelling, however. Look at the mass desertion at Royal Bank of Scotland's Coutts office in Singapore, for example, where staff have gone elsewhere because the British bank, mostly taxpayer-owned, is so constrained on its bonus policy.

This is not to say the Government should not be tackling the bonuses paid by institutions with which it does have influence – of course it should – or that it should not take to task G20 partners reneging on the deal, which it must. But to pretend we have worldwide consensus on bonuses that will see no country disadvantaged would be dishonest.