Three years ago, eight British servicemen were detained by Iran after a similar confrontation.

Former Marine Scott Fallon was one of those captured.

He told BBC Radio Five Live he was subjected to mock executions and accused of spying.

"They just wanted to know our mission - why we were there, why we were in Iran.

"We had no answers to these questions. Our mission was in Iraq, where we were... I suppose the same thing will be going on with these guys.

"You don't know if they're trying maybe to pin something else onto you. In our case it was being accused of spies in Iran, which was all new to us".