Jersey and Guernsey are planning to move quickly to allay uncertainty over their corporate tax regimes in the wake of a warning that they conflict with the “spirit” of European Union rules on harmful tax competition.

Objections by some EU member states to the islands’ tax systems, under which many companies pay zero corporation tax, were conveyed to them last week by Stephen Timms, Treasury minister. The move may be the start of a new phase in the assault on tax havens that until now has focused on bank secrecy.