Thanks for the replies.

I raised this problem with the park warden back in 2007 but no action seems to have been taken. I have posted a message to Southwark council.

The problem is caused by professional dog walkers and not dog owners walking their dogs.

I agree that many dog owners would be shocked to discover the amount of dogs that the walkers walk at one time and the general lack of attention the dog walkers show the dogs but I will leave that for someone else to write about. I only posted my message since I was concerned about the destruction of one tree hill.