For the last 12-18months i've been getting really odd weeds that has taken over my lawn and in fact now, has badly messed it up that i shall need to sort out a new one.
I've never seen it before, and they are only growing in the lawn not flower beds.

It is like roots of a tree growing up. I've tried digging them out, but they go straight down about a foot and then shoot off sidewards and carrys on to god knows how far.
I notice the ground comes up in a large hill then after a while little shoots like spikes come up and they lead to these brown root like things.

I shall take some photos in a week or so as i have smashed them all down due to the dog hurting her paws on the spikes.
Just wanted a rough idea to google search and get an idea what i'm dealing with.

I'd really appreciate any help
Thank you for your time.