[annalex]

I don’t see any evidence that structure was a septic tank. I see though evidence of a useful idiot of the Left trusting the mass media.

[RegulatorCountry]

Ordinance survey maps from 1840 onward show the structure on the site in question and label it a septic tank, annalex. The tank was no longer used for sewage after 1938, when a new sewer system came into use.