Anyone hoping for a concerted effort to boost global growth will have been disappointed by the familiar combination of bland public conclusions and behind the scenes sniping at the G20 gathering in Shanghai. Policymakers committed to use all tools — monetary, fiscal and structural — to strengthen the recovery. But in reality, many are deferring difficult reforms and hoping that others will shoulder the burden of fiscal expansion. As for monetary policy, there is a clear concern that the latest weapon in central banks’ armoury — the adoption of negative interest rates — may amount to little more than a new way to wage an old-fashioned, beggar-thy-neighbour currency war.

Mark Carney, the Bank of England governor, set out this concern most forcefully. It is critical for central banks to structure stimulus measures in ways that boost domestic demand, he argued, so that a “rising tide” of global demand could “l(fā)ift all boats”.

Negative interest rates are intended to achieve this, forcing banks to seek out riskier lending opportunities and assets, and encouraging consumers and borrowers to spend. It is plausible and technically possible for them to do so. However, many banks, and policymakers, are proving unwilling to make retail customers feel the full effects.