Neighbour's sewage/foul water leak

[Koumak]

Looking for help in reporting and helping with sewage leak.
We have had a problem with neighbour’s foul water leaking onto our property for months!!!
Although they have called a plumber in and supposedly cleared some blockage the leak is still there.

Next door terraced house, i.e. the leak is somewhere 1m away from our property.
Literally their sewage is leaking right under our feet as soon as we open the garden door.

This is the only access to our garden where 2 small children play daily.
The foul water has not entered our property but it is obviously unsanitary to have to cross it when we need to go to garden, it is also smelly!
I believe we have been very patient with them while they apparently tried to fix it but it has been months!
First they thought it is a blocked sewer and promised it was dealt with. The issue remained. Then their plumber had a heart attack, yet they are refusing to call in ours….
The leak is getting bigger it seems and I am worried this is only a matter of days before it causes serious and permanent damage to our flat.
What can I do to push them? Is there a council department who will be interested in dealing with this? It is surely environmental and health nuisance? Would the company dealing with sewers be interest? Affinity Water supplies with water but I believe Thames Water is the one looking after waste?

We have a little stream near where we live and I remember they came to inspect all the properties years back to make sure all the plumbing goes to waste and only rain water to the stream etc.
How do I make them to sort this out asap!?
We are renting the flat out and it really upsets me that the family cannot enjoy the outdoor space. The neighbours don’t seem to get the urgency at all. In fact, they told me I am being unreasonable and to stop chasing them! They cannot see that I have duty of care. How can anyone be ok with raw sewage leaking is beyond me.

I think they don’t see the problem as much as it just goes all under their raised decking but it is constantly under my fence and our feet.
Please help!?

Yes absolutely call the council.

Environmental Health are here for just this kind of thing.

Thanks. I have tried looking at Barnet website but didn't get very far reporting it? They seem to be interested in the public leaks only? There is an online form where drop down menu doesn't give an option of private property at all.

Yes you need to report to environmental health. Looking at Barnet's website the number you need is 020 8359 7995. Probably can't do an online form, will need to call them

Thank you for the phone number! I have just sent them (Re Ltd Regulatory Services) email with a video taken earlier today. Fingers crossed!

Water company who deal with the waste, they are usually pretty hot on this because its a health hazard.

Do you know where the issue is? Is it their drain that connects to the sewer, or is it the sewer itself? That affects who might be responsible for sorting it.
I'd call the water company and report it, ask them to come and have a look ASAP.

Ask the water company for advice as well they may even come out and look or get the owners to do something , no harm in asking them as well as contacting eho

Are you absolutely sure it's the neighbour's sewage? In some streets the sewage outlets all join up.

I also tried Public health about a septic tank leak onto my garden, they said it was nothing to do with them 😣