A proposal to allow British busineses to opt out of a European emissions trading scheme is likely to be approved by the European parliament today.

Such a move would allow the 36 companies - including British Airways, BP and Barclays - who are already committed to a UK trading scheme, to continue trading emission credits until December 2006.

The government and the CBI strongly support the opt out of the European scheme, arguing that a switch of regulatory regimes would cause unnecessary disruption to businesses.