I suggest you take a break from the law. Whether something is theft does not depend on whether one is caught and convicted. If I see someone drop a pound coin and I keep it, that is theft.
If I just find the coin with no sign of the owner, that is not. The difference is dishonesty, which is present in the first case but not the latter.
s.1 Theft Act 1968 (I had to learn this by heart at college)
A person is guilty of theft if he dishonestly appropriates property belonging to another with the intention of permanently depriving the other of it; and “thief” and “steal” shall be construed accordingly.
Yes, I agree with you
here.