NATO's new defence strategy in doubt without 'Europe's biggest security provider'

US Secretary of State John Kerry (L) and members of his delegation take their places at the table opposite NATO Secretary General Jens Stoltenberg (R) and his delegation ahead of a meeting at the NATO headquarters in Brussels. Getty Images

Robin Emmott

Britain's departure from the European Union risks undermining Europe's new defence strategy, days before Nato and EU governments sign a landmark pact to confront a range of threats from Russia to the Mediterranean, officials say.

The European Union and the United States plan to use two separate EU and Nato summits in the coming days to push reforms of the West's two main security pillars, aimed at reducing Europe's reliance on Washington in its own neighbourhood.