Does anyone know what this weed is?

This weed is taking over our lawn - front and back. Its stems creep and multiply - It has purple clover like flowers and it is very difficult to remove. Stems are quite thick
See photos of stuff already removed leaving big areas we have to fill in with new grass.

 

https://en.wikipedia.org/wiki/Prunella_vulgaris

 

Thank you but I don't think its Prunella JazzSi - the leaves are not lance shaped but rounder and the flower is different. My awful pest doesn't grown upwards (2 - 12" high) it creeps along the ground and seems to hide in the grass - I have never seen it anywhere else.

 

Thank you Marley, the leaves certainly look like the common type of ajuga which I used to have in my beds and replaced them by the chocolate coloured one which isn't as rampant. I have though noticed a few chocolate ajugas in the lawn but they are very easy to see and easily removed.
I looked up ajugas and there is one called Ajuga Rampant which would fit the type spreading through my lawn. So it may be a warning for people NOT to plant the old ajugas next to a lawn.

However Ajuga is not 'self-heal' - the Prunella mentioned above is self heal so I can only surmise that my pest is one of these two. Thank you again both.

 

you need a lawn lawn mower, in this case..