When did Yateley Common first achieve SSSI status?

The very first designation of an SSSI was in 1978 and was only 218 hectares. This was all common land and was most of the common east of Cricket Hill Lane ie the County and MOD parts. The citation was very short and only mentioned two of the Annex 1 birds, although Nightjars flew right down to our house at that time because we were surrounded by open fields.