I don't know about ranking but: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/644968/UK_National_Risk_Register

I don't know about ranking but: https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/644968/UK_National_Risk_Register_2017.pdf https://assets.publishing.service.gov.uk/government/uploads/... page 35 it is on the national risk register. Here is the preparedness strategy (from 2015): https://assets.publishing.service.gov.uk/government/uploads/system/uploads/attachment_data/file/449593/BIS-15-457-space-weather-preparedness-strategy.pdf https://assets.publishing.service.gov.uk/government/uploads/... The GB network tends to have relatively short lines and has used a GIC resistant transformer design since the 1990s so would probably only lose 1% or so of its transformers in a Carrington event. Three phase transformers with five limb cores are particularly vulnerable and have not been installed since 1997 on the GB grid.