Funeral directors. Just to watch the chaos in the weeks after.
Everyone else is replaceable.
Funeral directors are localised knocking a few out of the picture could cripple a council, They wouldn't be able to get anyone in, because all of them would be flat out nationwide, So a pile of corpses, and negative public opinion would rise. Not to mention the anger, and potential for a bad quick solution... Far more damaging than anyone else I can think of as a target. It could take years to fully resolve, end careers, cause riots ect.