Finance Bill

I am grateful to the hon. Lady for her answer a few moments ago, but I seek a little clarification. Is that 0.6 per cent. of the total emissions from UK aircraft or 0.6 per cent. of a million tonnes of carbon? Also, will the efficiency of different plane models be taken into account so that some aircraft could be taxed more or less than others—in other words, will there be an incentive to use more efficient planes?