LONDON (AP) — Bank of England Governor Mark Carney says Britain's exit from the European Union is a "litmus test" for a responsible global financial system.

He says it should be possible for Britain and the bloc to negotiate an exit and new relationship that takes the "high road" of a "new responsible global financial system."

Carney says the alternative is a protectionist path in which "trust and cooperation diminish, fragmentation hardens, capital flows are disrupted and trade and innovation are curtailed."

U.K.-based banks can currently do business seamlessly across the 28-nation bloc, but that may no longer be the case after Brexit.

In a speech Friday, Carney said the central bank had asked London-based financial firms to submit contingency plans for all possible Brexit outcomes — including a failure of the talks.