The Elfin Oak stands in Kensington Gardens. The stump, which is from a 900 year old tree, came from Richmond Park and was brought to Kensington in 1928. Over the next two years Ivor Innes carved and painted elves and animals into its surface so the appear to be climbing the tree.
Photo by Uli Harder (https://www.flickr.com/photos/uli_harder/)
photo by Tracy Lee Carroll (https://www.flickr.com/photos/tracylee/)
photo by Tracy Lee Carroll (https://www.flickr.com/photos/tracylee/)
In 1966 a campiagn led by comedian Spike Milligan resulted in its restoration and being declared a protected monument.
photo by Tracy Lee Carroll (https://www.flickr.com/photos/tracylee/)
Pete's Favourite Things 
Did the lady in the first picture make it – the guy seems to be pretty good at mouth to mouth!
I would imagine it was considered fairly risqué for a public piece of sculpture when originally put on display.