European tax commissioner Algirdas Semeta has indicated the European Union could challenge the legality of the UK-Swiss tax deal.
The UK and Switzerland governments recently signed a controversial agreement to tax money held by British citizens in secret Swiss bank accounts.
Last week Semeta addressed the EU Parliament and talked about the UK-Swiss and similar German tax deals. He implied that the German deal was illegal on the basis of the tax rates in operation.
Richard Murphy, of Tax Research UK, said in his blog: