Overview

• The 2025 CAGE study by Warwick University economists analysed five years of fuel data to quantify the RTFO’s contribution to consumer prices.
• Researchers found rising ethanol costs and stricter blending targets have driven up petrol by 3.5p per litre and diesel by six pence.
• Drivers now pay an average of 134.64p per litre for unleaded petrol and 141.95p for diesel, as tracked by RAC Fuel Watch.
• E10 petrol, containing up to 10% ethanol, has been the UK standard fuel since 2021; non-compatible vehicles can still access E5 as a 97+ octane super grade.
• Incorporating bioethanol under the RTFO has reduced fuel economy by around 1%, though the government considers the effect negligible for everyday driving.