German banks are facing fresh scrutiny over vault security after one of the largest robberies on record left more than 3,000 customers facing losses estimated at tens of millions of euros. Thieves broke into a Sparkasse branch in the western German city of Gelsenkirchen over the Christmas holidays, obtaining access from an adjacent multistorey car park through an emergency exit before drilling into the vault and forcing open almost all of its 3,250-odd safe deposit boxes.