▁was ▁found ▁that   – ▁apart ▁from ▁the ▁bomb ▁damage   – ▁the ▁tunnel ▁had ▁surv ived ▁sevent y ▁years ▁of ▁use ▁in ▁excellent ▁condition . ▁ ▁The ▁sub way ▁today ▁ ▁While ▁it ▁is ▁no ▁longer ▁used ▁for ▁hyd ra ul ic ▁tub es , ▁the ▁tunnel ▁still ▁car ries ▁water ▁main s . ▁The ▁hyd ra ul ic ▁tub es , ▁once ▁a ▁major ▁source ▁of ▁power ▁in ▁the ▁centre ▁of ▁London , ▁have ▁since ▁been ▁replaced ▁by ▁tele communic ation ▁c ables . ▁ ▁A ▁small ▁round ▁entrance ▁building ▁surv ives ▁at ▁Tower ▁Hill ▁near ▁the ▁Tower ▁of ▁London ' s ▁ticket ▁office , ▁a ▁short ▁distance ▁to ▁the ▁west ▁of ▁the ▁main ▁entrance ▁to ▁the ▁Tower . ▁This ▁is ▁not ▁the ▁original ▁entrance , ▁but ▁was ▁built ▁in ▁ 1 9 2 6 ▁by ▁the ▁London ▁H yd ra ul ic ▁Power ▁Company , ▁with ▁a ▁ring ▁of ▁letter ing ▁giving ▁the ▁original ▁date ▁of ▁construction ▁and ▁naming ▁the ▁L HP C . ▁The ▁entrance ▁on ▁the ▁south ▁bank ▁of ▁the ▁Th ames ▁was ▁demol ished ▁in ▁the ▁ 1 9 9 0 s , ▁and ▁a ▁new ▁one ▁has ▁been ▁built ▁in ▁its ▁place . ▁It ▁is ▁located ▁just ▁behind ▁the ▁Un ic orn ▁Theatre ▁on ▁To ole y ▁Street , ▁but ▁there ▁is ▁no ▁pla que ▁to ▁mark ▁the ▁site . ▁ ▁See ▁also ▁T unn els ▁under ne ath ▁the ▁River ▁Th ames ▁List ▁of ▁cross ings ▁of ▁the ▁River ▁Th ames ▁ ▁References ▁ ▁External