Opened in 1943 and closed in 1961. On common land on the east side of Knavesmire Road.
EXTANT Two groups were formed in 1937, 9 Group covering the North Riding of Yorkshire and 10 Group covering the East Riding of Yorkshire and northern part of Lincolnshire. In the reorganisation of 1953 the Northern part of 10 Group was attached to 9 Group and redesigned 20 Group while the remaining southern part was attached to Leeds and redesigned 18 Group (Yeadon). In the re-organisation of 1968 18 Group was disbanded, its territory covering the East and West Ridings of Yorkshire was transferred to 20 Group (York) while that in North Lincolnshire transferred to 15 Group (Lincoln). The northern posts of the previous 20 Group transferred to 23 Group (Durham).
Two purpose built prefabricated buildings, one for 10 Group and the other for 9 (later 20) Group were constructed in 1943. They were on common land at Knavesmire on the south side of York and were 100 yards apart. The Group Control for 10 Group was operational from 1943 - 1953 and that for 9⁄20 Group was operational from 1943 - 1961. A new protected control centre was opened at Acomb in December 1961. 10 Group Control has been demolished but 9⁄20 Group Control still stands. It is still on common ground and is now used as a changing room by the Hamilton Panthers Rugby Club. It was not possible to see the interior of the building but the two-storey brick operation room and the three single prefabricated administration blocks surrounding it are externally still in good condition.