ui ▁in ▁Japan . ▁The ▁clim bing ▁c ran es ▁used ▁to ▁ere ct ▁the ▁tower ▁port als ▁were ▁coinc ident ally ▁also ▁used ▁on ▁the ▁H SB C ▁Main ▁Building ▁a ▁de cade ▁earlier , ▁as ▁well ▁as ▁at ▁Can ary ▁Wh arf ▁in ▁the ▁inter im . ▁ ▁In aug uration ▁ ▁Const ruction ▁was ▁finished ▁in ▁May ▁ 1 9 9 7 . ▁It ▁cost ▁H K $ 7 . 2 ▁billion . ▁The ▁L ant au ▁Link , ▁of ▁which ▁the ▁bridge ▁is ▁an ▁integral ▁part , ▁was ▁inaugur ated ▁on ▁ 2 7 ▁April ▁ 1 9 9 7 ▁by ▁former ▁British ▁Prime ▁Minister ▁Margaret ▁Th atch er . ▁Security ▁was ▁extremely ▁tight ▁as ▁Th atch er ▁was ▁considered ▁one ▁of ▁the ▁top ▁targets ▁of ▁the ▁Irish ▁Republican ▁Army . ▁ ▁The ▁comm em oration ▁ceremony ▁began ▁with ▁a ▁fl ot illa ▁of ▁police ▁and ▁other ▁government ▁vessels ▁passing ▁beneath ▁the ▁bridge , ▁before ▁Government ▁F lying ▁Service ▁and ▁Royal ▁Air ▁Force ▁aircraft ▁fle w ▁above ▁the ▁concrete ▁to wers . ▁Th atch er , ▁Chief ▁Secretary ▁An son ▁Chan , ▁and ▁Governor ▁Chris ▁Pat ten ▁then ▁switched ▁on ▁the ▁bridge ▁lights ▁and ▁drove ▁across ▁the ▁span ▁with ▁other ▁dign itar ies . ▁The ▁celebr ation ▁concluded ▁with ▁a ▁ 2 0 - min ute ▁fire work ▁and ▁las er ▁show , ▁featuring ▁fire ▁pour ing ▁from ▁the ▁length ▁of ▁the ▁bridge , ▁engine ered ▁by ▁the ▁Py rom ag ic ▁Produ ctions ▁company . ▁Chief ▁Executive -