National supervisors should communicate with peers in other countries early on in their rule-making to prevent the kind of cross-border discrepancies that have plagued derivatives clearing, according to regulatory and industry representatives.

"What we need to do in the future is co-operate much more before we pick up a pen to write the rules. We should agree definitions, scope and timing, because once a law is implemented it can become the most inelastic good in the market, and no-one wants to