This is a rare example of a working BT Booth 7A, also known as an Oakham Booth as its shape resembles that of an Oak ham tin. This type of Booth was used by BT in areas of high vandalism, such as areas where the normal Kiosks were set on fire etc. This example although functional is in terrible condition, and the area by the station where it is situated is dark and isolated, not a phone I would personally use alone in the nigh time.
Source: http://www.waymarking.com/waymarks/WM26AG_Penmaenmawr_Railway_station_Wales