As the powerful head of the FBI, James Comey lobbed one bombshell after another into the world of American politics - until the politics came back to bite.

Dismissed by president Donald Trump in a shock announcement on Tuesday, less than halfway into his 10-year term, Mr Comey played a deeply controversial role in the run-up to last year's election - and beyond.

First, he hampered Hillary Clinton's White House bid with a damning assessment of her email practices as secretary of state - reopening the case days before the vote in a move the Democrat says cost her the election.

When Mr Trump decided to keep Mr Comey - who was appointed by Barack Obama - in his job, it raised eyebrows from critics who saw it as a tacit reward for his role in damaging Mrs Clinton's chances.

But the FBI chief had increasingly appeared to be a thorn in the president's side.