I have seen sign posts in England at road junctions in different counties that mark the way to go as you are driving. Many consist of fingerposts to show the direction to different points of interest or villages. In the county of Dorset, they have some that are more unique to that county. They have road signs topped with finials.
The final is unique in appearance. Many are shaped like a London underground sign. While others are circular in shape. On the top part of the circle (on ones shaped like an underground sign) lists the county, Dorset, in case you are not sure. The bottom of the circle lists the grid reference. If it has a rectangular shape in the middle like a London Underground sign, it tells you the specific location of the sign.
According to Colin and Susy Varndell, authors of The Natural Beauty of Dorset, many of these fingerpost road signs were removed in 1940. The government decided that these signs could aid the enemy if they invaded. Many of the signs were sent for scrap with the finials. Councils are replacing these signs and adding finals back on the top with help of individuals, parishes, companies, or groups.
While other counties may have a few of these, they seem to be more common in Dorset. When in Dorset, England see how many finials you can find when on your travels. It is something that makes Dorset unique.