Andy Cap wrote:

18 of our semis are served by what was a private sewer along the rear of
the properties. When that blocked the same argument ensued, with those
up the road refusing to contribute. The Council took the problem over,
added 10% and split the bill across all the properties. Fortunately now
as I understand it, the Water companies have taken them over.

Yes, nicely summarised here

http://www.water.org.uk/home/policy/private-sewers-transfer/customer-info/before-after

Similarly, the water companies seem set to take over private sewage
pumping stations by 2016.