▁to ▁rel ieve ▁traffic ▁con g estion ▁west ▁of ▁London , ▁it ▁car ries ▁the ▁A 3 1 6 ▁road ▁between ▁Ch is wick ▁on ▁the ▁north ▁bank ▁of ▁the ▁Th ames ▁and ▁Mort la ke ▁on ▁the ▁south ▁bank . ▁ ▁Bu ilt ▁on ▁the ▁site ▁of ▁a ▁former ▁fer ry , ▁the ▁bridge ▁is ▁ ▁long ▁and ▁faced ▁with ▁ 3 , 4 0 0 ▁tons ▁of ▁Port land ▁stone . ▁At ▁the ▁time ▁of ▁its ▁opening ▁its ▁ ▁central ▁span ▁was ▁the ▁longest ▁concrete ▁span ▁over ▁the ▁Th ames . ▁The ▁bridge ▁is ▁possibly ▁best ▁known ▁today ▁for ▁its ▁proxim ity ▁to ▁the ▁end ▁of ▁The ▁Championship ▁Cour se , ▁the ▁stretch ▁of ▁the ▁Th ames ▁used ▁for ▁the ▁Bo at ▁Race ▁and ▁other ▁row ing ▁races . ▁ ▁Background ▁The ▁villages ▁of ▁Ch is wick ▁and ▁Mort la ke , ▁about ▁ ▁west ▁of ▁central ▁London ▁on ▁the ▁north ▁and ▁south ▁banks ▁of ▁the ▁River ▁Th ames , ▁had ▁been ▁linked ▁by ▁a ▁fer ry ▁since ▁at ▁least ▁the ▁ 1 7 th   century . ▁Both ▁areas ▁were ▁sp ars ely ▁populated , ▁so ▁there ▁was ▁little ▁demand ▁for ▁a ▁fixed ▁river ▁crossing ▁at ▁that ▁point . ▁ ▁With ▁the ▁arrival ▁of ▁rail ways ▁and ▁the ▁London ▁Under ground ▁in ▁the ▁ 1 9 th ▁century ▁comm uting ▁to ▁London ▁became ▁practical ▁and ▁afford able , ▁and ▁the ▁populations ▁of ▁Ch is wick ▁and ▁Mort la ke ▁grew ▁rapidly . ▁In ▁ 1 9 0 9 ▁the ▁Great