Exclusive: NatWest, Microsoft and GSK among firms to raise complaint over poor planning and breakdown in relations

Companies that stumped up millions of pounds to sponsor the Cop26 climate summit have condemned it as “mismanaged” and “very last minute” in a volley of complaints as next month’s event in Glasgow draws near.

The sponsors, which include some of Britain’s biggest companies, have raised formal complaints blaming “very inexperienced” civil servants for delayed decisions, poor communication and a breakdown in relations between the organisers and firms in the run-up to the landmark talks.