, ▁to ▁address ▁such ▁issues ▁within ▁female ▁pr isons , ▁consult ing ▁former ▁prisoners , ▁and ▁organis ations ▁such ▁as ▁N AC RO ▁and ▁the ▁Pr ison ▁Officer ' s ▁Association . ▁ ▁Fil ming ▁The ▁series ▁was ▁commission ed ▁by ▁I TV ▁under ▁the ▁working ▁title ▁J ail ▁Bird s ▁and ▁comm enced ▁film ing ▁in ▁February ▁ 1 9 9 9 . ▁However ▁the ▁show ' s ▁name ▁was ▁later ▁changed ▁after ▁a ▁BBC ▁One ▁document ary ▁series ▁about ▁women ▁in ▁prison ▁used ▁the ▁same ▁title ▁a ▁few ▁months ▁before ▁the ▁first ▁series ▁was ▁a ired . ▁ ▁The ▁exact ▁location ▁of ▁the ▁fict ional ▁H MP ▁L ark hall ▁was ▁never ▁revealed , ▁although ▁in ▁Series ▁One , ▁E pisode ▁Four , ▁character ▁Sh ell ▁D ock ley ▁mentioned ▁it ▁was ▁' not ▁far ' ▁from ▁Cla ph am . ▁There ▁were ▁several ▁other ▁references ▁through ▁the ▁series ▁that ▁all ud ed ▁to ▁it ▁being ▁in ▁the ▁South ▁London ▁region , ▁but ▁no ▁specific ▁location ▁was ▁given . ▁Several ▁districts ▁of ▁the ▁London ▁area ▁were ▁referenced ▁throughout ▁the ▁series ▁run , ▁these ▁include : ▁Pe ck ham , ▁Cla ph am , ▁Act on , ▁Cat ford , ▁Stre ath am , ▁Sy den ham , ▁To oting , ▁Str at ford , ▁Bal ham , ▁and ▁Beth nal ▁Green . ▁ ▁The ▁interior ▁of ▁the ▁prison ▁is ▁also ▁seen ▁in ▁Water lo o ▁Road ▁season ▁ 3 , ▁episode ▁ 1 1 . ▁ ▁H M ▁Pr ison ▁Oxford