Is the UK's special relationship with US under threat?

What started as a leak of secret diplomatic memos to a British tabloid newspaper has led to the resignation of a top ambassador and questions about the UK's position in the world.

Kim Darroch felt compelled to quit as Britain's envoy in Washington after a row over leaked memos.

The diplomat had described Donald Trump and his administation as insecure, inept and dysfunctional.

The U.S. President responded with a barrage of angry tweets, calling Darroch ''very stupid.''

Boris Johnson, Britain's likely next prime minister, refused to publicly support the ambassador.

So how will this incident affect the UK's ties with its closest ally?