LONDON - The European Union should allow its banks to continue clearing euro derivatives in London and avoid being "protectionist" in financial markets, London Stock Exchange Chief Executive David Schwimmer said on Tuesday.

Britain's full departure from the EU has largely severed the City of London's ties with the bloc, and EU permission for the London Stock Exchange to keep clearing euro derivatives for EU customers expires in June next year.

The EU's executive commission is asking banks and asset managers how quickly they can shift trillions of euros in derivatives clearing from London to Deutsche Boerse in Frankfurt and if legislation is needed.

"I think it's critically important for the EU to remain open and to resist the protectionist temptation," Schwimmer told a European Financial Services conference.

"What has made the EU so successful is its openness to the world and being able to embed itself in global ecosystems."

EU firms should be able to access the same liquidity, services, data and technology capabilities as their peers in respect to clearing, Schwimmer said.

"I am not arguing for an absence of control by the EU over important strategic areas," he said, adding: "I really hope that the dialogue and cross border access that we have today can prevail going forward."

(Reporting by Huw Jones; Editing by Alexander Smith) ((huw.jones@thomsonreuters.com; +44 207 542 3326; Reuters Messaging: huw.jones.thomsonreuters.com@reuters.net))