I found what I believe to be a tooth on the sea shore at Walton on the Naze. Initially I thought it was some kind of sharks tooth, however because it has a rounded profile and doesn't resemble any sharks teeth that I have seen I'm not certain that it is.
Perhaps someone would be able to identify it more accurately for me.
Keith is spot on, it is just flint I'm afraid. I've attached an info sheet to find out more about flint.
If you are looking for fossils at Walton again, here are some useful links for Walton and London Clay fossils in general:
Hope that helps,
Earth Sciences ID Officer