Environment secretary Margaret Beckett visited Shell's trading floor to take part in the UK's Emissions Trading Scheme (ETS).
She traded greenhouse gases through the newly created Emissions Registry to find out how the scheme works. The ETS is a key part of the government's Climate Change Programme, and the world's first economy-wide greenhouse gas emissions trading scheme.

The Registry records the holdings of allowances by participants in the ETS, which is currently voluntary. Allowances are tracked from their initial allocation through all transfers of ownership to their final cancellation or retirement. One allowance is equivalent to one tonne of CO2.

Beckett commented: "Emissions trading will allow organisations to reduce their emissions of greenhouse gases in the most economically efficient way. It is a central feature of the Kyoto Protocol, and the European Commission has proposed that EU-wide trading should begin in 2005."

Clive Mather, Shell UK's country chairman added: "We believe that market mechanisms are the best way of achieving the maximum reduction in emissions at minimum cost to society. The trading floor is a demonstration of that prinicple in action."