This is a global issue since nearly all commercial flight training involves fuel incorporating TEL since it reduces the risk of engine misfires with potentially serious consequences for aircraft safety. The use of fuel incorporating TEL is widespread across many countries’ GA sectors, including the United States and many European countries, where it is the dominant fuel used for piston engine aircraft.
The Department for the Environment, Food, and Rural Affairs leads the development of the UK REACH alongside the Health & Safety Executive (HSE). My officials engaged with them to understand the legal status of TEL in the EU, as well as to understand how the UK REACH regulations would work. No country globally has banned TEL. The HSE recently announced that they would not include TEL in their list of authorised chemicals under the UK REACH as they judged that with intensive efforts already ongoing to find a substitute, additional regulatory pressure is unlikely to speed this up keeping the UK in line with the EU, but would revisit this when substitutes had been tested and certified.
Aside from noting whether TEL would be assessed for inclusion in Annex 14 of UK REACH, neither my officials, myself nor the Secretary of State have engaged either organisation to influence their decision.
In response to an enquiry by the Aircraft Owners and Pilots Association about the future of 100LL the Secretary of State asked his officials to speed up work on finding safe alternative unleaded fuel such as UL91. This is highly technical safety work involving the FAA, EASA and engine manufacturers in which the UK seeks to play a leading part.