Should Donald Trump's state visit be called off?

US President Donald Trump has caused quite some furore over his tweets.

After retweeting right-wing Islamophobic videos, he told Theresa May to focus on what he called was Britain's "destructive Radical Islamic Terrorism."

It has led to calls for the president's state visit to be called off.

The BBC's deputy political editor John Pienaar explains why that could have led to "full blown diplomatic crisis".