This is around 8 miles from central Cambridge. Unless your walking’s really adventurous, you’d reach the camp more readily by bus or bike than on foot.
Oakington Immigration Reception Centre was used by the Home Office from 2000 to detain asylum seekers while their claims for refugee status were assessed; it also held foreign prisoners. The harsh conditions and management were repeatedly strongly criticised. Local volunteers actively endeavoured to support those held there. This centre was closed in 2010, but other UK detention centres remain.
Oakington Immigration Reception Centre had previously been a barracks, and before that an RAF airfield. Present plans are to incorporate it into the new village of Northstowe, some streets of which have been built around it.