The issue focused on technology used by electronic devices in cars to detect whether they have been tampered with. "There was not any technological hardware there that could tell me if it had been switched off," she said.

She added: "We're running software systems that can tell us when we've lost internet connectivity and how long it has been gone for. But at the moment, there's no digital sensors or cameras that can tell you what happened or where it was."

Many websites run software which