World Rugby has made a law amendment after George North scored a try while England were down to 13 men to help Wales to victory on Saturday.

North's try came after England's Anthony Watson was sent off and before a head injury replacement for Willi Heinz had come on.

The amendment states that play can only restart once temporary replacement players are on the field.

The change comes less than a month before the Rugby World Cup in Japan.

Wales became world number one after the 13-6 win and begin their World Cup campaign against Georgia on 23 September, while England's first match is against Tonga on 22 September.