I've only been to Southend once. Someone tried to rob us on the train home, there was a fight because if you're going to steam a train, don't pick the post-pub express. I ended up sat on struggling robber for thirty minutes trying to persuade several other passengers that murder was still a crime in Essex (I think and to be honest he wasn't very appreciative of my efforts). The driver ignored the alarm till Shenfield, where he got off, peeked through the window and ran away (we never saw him again). Eventually, we let the wannabe robbers escape because we wanted to go home and the police hadn't shown up. About 3am, two PCs appeared. the station was locked apparently, they'd been outside waiting to be let in. So anyway, they left empty-handed, at which point we were left on our own train in the middle of an empty, unstaffed station. Many, many calls later someone appeared and probably regretted it, has he to arrange taxis for about 100 people. I think we got home at 6am.
So yes, build the wall. Around Essex.