In the wake of the widespread chaos that accompanied the bankruptcy of Lehman Brothers last September, regulators have sought to find a better way to unwind global financial giants. One approach is that the banks themselves should prepare for their own orderly demise -- a kind of "living will".

That idea has been gathering steam of late. The G20 group of finance ministers and central bankers meeting in London over the weekend agreed to require "systemic firms to develop firm-specific contingency plans."

The concept has wide appeal. The crisis has convinced politicians and regulators of all colours that even large financial institutions must be allowed to fail without imposing a huge burden on taxpayers. Many bankers see such a regime as a preferable alternative to more intrusive regulation.

However, drawing up a detailed "living will" is easier said than done.

Simon Gleeson of Clifford Chance argues that it is more important for regulators and legislators to establish a cross-border crisis-management and resolution regime than it is for individual firms to prepare for their own demise.

The mandate of the Financial Stability Board (FSB), the international body comprising finance ministries, central banks and financial regulators, was recently expanded to include contingency planning for cross-border crises. It published a series of relevant principles in April. However, as the Institute of International Finance (IIF) noted, it is "clear from the high-level nature of the principles and the aspirational language [that] there remains a lot to be done."