Theresa May has branded the latest action by North Korea "reckless and unacceptable."

The Prime Minister said in a statement: "This latest action by North Korea is reckless and poses an unacceptable further threat to the international community.

"I discussed the serious and grave threat these dangerous and illegal actions present with President Abe in Japan this week and reiterate the call we jointly made for tougher action, including increasing the pace of implementation of existing sanctions and looking urgently in the UN Security Council at new measures.

"This is now even more pressing. The international community has universally condemned this test and must come together to continue to increase the pressure on North Korea's leaders to stop their destabilising actions."