Bretton Kent

It certainly looks like a serrated thresher to me, as the serrations are too large for megalodon. The mesial cutting edge is broadly convex; in megalodon from similar tooth positions it would be more sigmoidal. Also, although the shape of the root lobes is typical of the giant threshers. The one odd feature is that the neck appears wide on the lingual face, but this is probably due to poor preservation. I have examined a serrated thresher where half of the tooth was exposed for some period of time, while the other half was protected in the matrix. The exposed half had a broad, rather irregular neck area as on this tooth, while the protected half was better preserved and had the typical narrow neck of a thresher.