James Comey, the former head of the FBI, has finally blown his own online cover, confirming the existence of his secret Twitter account.

"Goodbye Iowa. On the road home," he wrote on Monday, alongside a photograph showing him standing in the middle of a road. "Gotta get back to writing. Will try to tweet in useful ways."

Mr Comey has kept a low profile since being fired by President Donald Trump in May, at a time when he was leading the federal investigation into Russian meddling in last year’s election.

In one of his few public appearances, giving testimony to Congress a month later, he suggested he was dismissed after being asked to back off part of the probe.

He is currently writing a book due in the spring and which critics of Mr Trump hope will include more revelations about his relationship with the president. Now they have an extra source to monitor for damaging nuggets.