Leaders of some of the world's biggest businesses on Thursday increased the pressure on the Group of Eight industrialised nations ahead of a summit on global warming, urging them to set up a system of emissions trading for greenhouse gases that would extend to 2030 and beyond.

Business representatives of companies including Toyota, BP and Ford, met Tony Blair, UK prime minister, to discuss climate change. Mr Blair has made the issue one of two priorities, along with Africa, for the G8 summit under the UK's chairmanship in Scotland in July.