Question to the Department for Transport:

To ask the Secretary of State for Transport, what steps his Department is taking to monitor the effect of E10 fuel on (a) emissions and (b) fuel consumption.

E10 has been the industry agreed standard for petrol since 2013, and the reference fuel against which new cars are tested for emissions and performance since 2016. The impact assessment published alongside the Motor Fuel (Composition and Content) and the Biofuel (Labelling) (Amendment) (No. 2) Regulations 2021, which introduced E10, estimates that the change from E5 unleaded petrol to E10 is expected to reduce CO₂ emissions by around 0.7 to 0.8 megatonnes per year. Switching from E5 to E10 is understood to have a relatively small impact on fuel economy of around 1-2 % and this was factored into the impact assessment. There are many factors that influence fuel consumption, making the effect of E10 difficult to assess on the basis of anecdotal evidence or monitoring. The Regulations mandating E10 petrol across Great Britain came into force just last September and will be the subject of a regulatory review considering its impacts, conducted within five years.