mohammed tahir , 53 , of leytonstone , east london , got off his train at mile end and picked a target on the platform - a ` confident and articulate ' professional in her 20s , a court heard .
he then followed her onto a central line service and stood as close to her as he could .
tahir sidled up to the victim and pretended to accidentally slide his hand across her thigh as she stood with other passengers in the busy carriage on a hot summer 's day .