Cameron has promised a referendum on pretty much any 'transfer of power' but then claims that this will apply to 'not just treaty changes but also taking Britain into the euro'. I wonder whether he plans to apply this to all passerelle clauses or just to treaty changes and decisions on monetary union. In any case, a Tory government would probably veto most moves to utilise a passerelle clause and any successor government could decide not to be bound by this law.