We have a 6ft wall, which people regularly climb over & break in to various homes in the street - what is a simple, economic way to construct a much higher security fence/glass/barbed wire type solution?
You will need to have a word with the police in your area - using material whch can be potentially harmful to anyone climbing over your barrier may leave you open to a legal case against you. I realise the apparent injustice of such a system, but the law is the law, and we are all bound by it. While you're asking for advice on the height and construction restrictions of your barrier, why not ask the police to send a few more patrols round, and see if they can eliminate your problem that way.
broken glass or razor wire, which form 'mantraps', or impaling spikes are often illegal* in urban areas - anti roll top is your best bet or a really nasty burglar paint applied often until they get the message - if you cant buy it make it yourself -