A key adviser to the European Union's highest court is siding against Britain and wants the EU cap on bankers' bonuses to be maintained.

Advocate General of the European Court of Justice Niilo Jaaskinen suggested Thursday that British attempts to derail the EU financial law "should be rejected," advising the court to dismiss the action.

EU legislation limits banking bonuses at one year's base salary and double that if a large majority of shareholders agree. The advice of the advocate general is confirmed in a majority of cases when the court itself makes a ruling, which is expected within months.

Britain says the rules will lead to an increase in bankers' fixed pay, drive away talent and weaken Europe's financial industry, the heart of which is in London's City.