Severn Trent Green Power published a statement on their Facebook page saying they could "confirm that at around 19:20 this evening, a digester tank at its Cassington AD facility near Yarnton, Oxfordshire, was struck by lightning resulting in the biogas within that tank igniting.

https://en.wikipedia.org/wiki/Lightning_rod

A lightning rod or lightning conductor (British English) is a metal rod mounted on a structure and intended to protect the structure from a lightning strike. If lightning hits the structure, it will preferentially strike the rod and be conducted to ground through a wire, instead of passing through the structure, where it could start a fire or cause electrocution.

The principle of the lightning rod was first detailed by Benjamin Franklin in Pennsylvania in 1755,[2] who in subsequent years developed his invention for household application (published in 1757) and made further improvements towards a reliable system around 1760.

This seems like the sort of thing that one could reasonably equip a facility with large tanks of explosive gas with in 2023.