The European Commission is embarking on revisions to the Markets in Financial Instruments Directive (Mifid) introduced three years ago. One of the expected changes is a clampdown on high-frequency trading and measures for more transparency in the algorithms that conduct much of daily trading. Rob Boardman, head of European trading at ITG, explains to Philip Stafford, why the market is facing tougher regulation and and outlines the difficulties regulators may face.