Yes, it is typically legal to add spikes on walls for security reasons. However, if you’re considering adding this extra measure to your security defence, it’s important to be aware of the related restrictions.
Anti-climb spikes and wall toppers can be used to deter intruders as long as they are not designed to cause serious bodily harm. Ideally, you should also display warning signs, as this will help prevent injuries.
It will also ensure that you remain compliant with relevant legislation, namely the Occupiers Liability Act of 1984, which states that property owners are responsible for protecting anyone on your property (yes, even intruders) from any harmful hazards.