Rising security costs, lack of planning and tensions between Scottish nationalists and the British government have cast a shadow of uncertainty over the UN’s COP 26 climate change summit.

Some 30,000 people, including 200 world leaders, are expected at the 10-day conference in Glasgow in November for crucial talks to halt rising global temperatures.

The Scottish Police Authority, however, has voiced concern at the cost of securing the event, putting the bill at an estimated £250 million ($325 million, 300 million euros).