Some of the reasons are nonsensical:
for trains:

"The fuel is subject to VAT at 5% on diesel and 20% on electricity.".

this should be the reverse?!?

for planes:

"Fuel accounts for a much bigger part of airlines’ costs, but they do not have to pay VAT or duty on it.".

whyyyy??
https://www.theguardian.com/lifeandstyle/2025/nov/19/why-are-flights-in-the-uk-so-often-cheaper-than-taking-the-train

#SaveThePlanet and tax planes in proportion of the damage they do to their environment!