Flat flood - can I claim?

I live on the ground floor of an 8 story flat. On August 2nd my flat started to flood, I couldn't find out where the water was coming from even after turning off all the pipes.
It turned out that there is a 4 inch cast iron drain pipe that runs down the inside of my flat, that goes from the roof all the way down to the ground.
This had become blocked and the water backed up the pipe and started to leak into my flat.
I called the council and they sent someone round to repair it.
However they said they couldn't as the manhole cover had been buried under the ground when a wheelchair ramp was built about 5 years ago, nobody raised the manhole cover.
I don't have contents insurance as I cannot afford it, and if I break something then it's my own fault. My wooden floor is now ruined and I don't feel it's my fault as it was beyond my control and due to the neglect of the council. They say that it should be claimed on my contents insurance.
Where do I stand with this?
They still have not repaired it and thankfully it has not rained since.
Many thanks, Cliff