Banstead Downs is situated south of Sutton, being bisected by the A217. This area used to be open chalk downland grazed by sheep and, 200-300 years ago, hosted a well known horse gallops that rivalled the nearby town of Epsom's. Today however it has largely scrubbed over, this growth accelerating in the past 30 years. Recent scrub clearance has been carried out and livestock placed to keep the vegetation down. A golf course is to be found on the western side.
For the naturalist the area is not particularly noteworthy for birds. A good cross-section of warblers breed (including Lesser Whitethroat) and passage of migrants is well pronounced (with the golf course worthy of checking). Grasshopper Warblers bred up until the 1970's and it is still possible to stumble across a singing Wood Warbler in the more wooded eastern area (and even, as one lucky observer did recently, Golden Oriole). The golf course to the west of the A217 is excellent for Firecrests. From the south end of Burdon Lane (accessible via Belmont Rise), the course is easily accessible and the wooded footpath on your right as you enter is the most reliable spot for wintering Firecrests.
The rarest bird that the site can boast is a Lesser Grey Shrike in 1956.
The area is outstanding botanically: Early Gentian and Broad-leaved Cudweed are the jewels in the crown. Among the healthy butterfly population includes Small Blue, Chalkhill Blue, Marbled White and small numbers of Dark Green Fritillary. Extensive moth trapping has revealed a rich and diverse collection of species.