Leaders of some of the world's biggest businesses yesterday 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, which included Toyota, BP, Ford, Siemens, Rio Tinto and ABB, met Tony Blair, the UK prime minister, for two hours 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.