The Grade II listed lodge stands at the Mansfield Road entrance to the Forest Recreation Ground which used to be a racecourse with the first meeting there taking place around 1690. A race stand was erected in 1777 where the Keeper of the Forest lived until the purpose built Lodge was built for him in 1857, by Henry Moses Wood.
It still has a police cell in the basement and occasionally the lower gate is unlocked so you can see this for yourself. It doesn’t seem to serve any particular purpose right now, but at least looks in a decent enough condition.
You can find a few more photos here.