s ▁director , ▁but ▁following ▁the ▁problems ▁with ▁the ▁Space ▁Wh ale ▁script ▁he ▁was ▁asked ▁to ▁hel m ▁its ▁replacement ▁due ▁to ▁his ▁experience , ▁and ▁so ▁F iona ▁C um ming ▁was ▁asked ▁to ▁take ▁over ▁En light en ment . ▁ ▁Once ▁production ▁began ▁it ▁became ▁apparent ▁that ▁Part ▁One ▁and ▁Part ▁Two ▁were ▁under - running ▁so ▁more ▁dialog ue ▁was ▁written ▁to ▁fill ▁in ▁the ▁time . ▁It ▁was ▁originally ▁intended ▁that ▁the ▁character ▁of ▁Jackson ▁would ▁not ▁re app ear ▁after ▁the ▁second ▁episode , ▁but ▁during ▁film ing ▁Sa ward ▁became ▁concerned ▁that ▁it ▁appeared ▁that ▁he ▁had ▁been ▁executed ▁and ▁so ▁he ▁and ▁C leg g ▁re w rote ▁Part ▁Three ▁to ▁include ▁him . ▁Part ▁Three ▁also ▁looked ▁to ▁be ▁under ▁running ▁so ▁scenes ▁from ▁Part ▁Four ▁were ▁brought ▁forward ▁and ▁the ▁final ▁scenes ▁with ▁the ▁Guard ians ▁were ▁extended ▁to ▁compens ate . ▁ ▁Cast ing ▁C um ming ▁came ▁up ▁with ▁the ▁idea ▁that ▁the ▁E tern als ▁would ▁not ▁bl ink ▁and ▁cast ▁actors ▁who ▁she ▁believed ▁could ▁provide ▁det ached ▁performances . ▁C um ming ▁re called ▁Peter ▁S all is ▁had ▁played ▁a ▁similarly ▁det ached ▁character ▁in ▁the ▁ 1 9 7 4 ▁BBC ▁drama ▁The ▁P all is ers , ▁and ▁cast ▁him ▁in ▁the ▁role ▁of ▁St ri ker . ▁S all is ▁was ▁present ▁during ▁the ▁re he ars als ▁for ▁the ▁serial ▁but ▁when ▁production ▁was ▁delayed ▁he ▁was ▁un available ▁for ▁the ▁new