Council refusing to deal with JKW properly

[LOVELYDOVEY05]

It has been 2 years now and all they have done is one treatment. The thing is spreading near next door which could make it difficult for them to sell We are tenants so not our duty. How can we get them to do the legal thing? We do not know if the neighbours know.
We are just leaving it to grow now as fed up with the Council

I'd tell your neighbours, tell them you have told the council but they may want to pursue it too as it will affect the saleability or mortgageability of their property if it spreads there

There is no legal requirement for a landowner to treat knotweed. However, the landowner must not allow it to spread into the wild. The neighbours may have a case for nuisance if their property is affected.

The fact you are tenants does not automatically mean it is not your responsibility. It depends on what it says in your lease and may also depend on whether or not the knotweed was present when you moved in.

Where is it? That will affect the legalities. But normally as a tenant your garden is your responsibility.