“It is the first time that we know of that a major lab has voluntarily slowed down.”

China’s regulator ordered changes after vehicle occupants sometimes had difficulty exiting electric cars, an issue that has led to lawsuits against Tesla in the United States.

The struggling firm said it had improved its performance but missed regulator-set delivery targets.

Negotiations to finalise a deal between the US and Canada are going down to the wire ahead of a Friday night deadline.

Economists said there were ongoing concerns over the level of borrowing as national debt passed $40tn.