-
Execution is not the only means by which the state kills people in order to enforce laws. The police are legally entitled to use force to prevent the comissioning of crimes, to apprehend offenders and to put people in custody, up and and including lethal force. Ultimately, all laws are backed up by the power of the state to physically coerce its citizens, up to and including lethal force. @mdcc_tester is spot on on this point. Quite often the state will just give up and go away, and leave laws unenforced - hence the vast amount of unpaid fines - but the threat of physical violence underpins any justice system.
Not in the UK. You just lock the person up or fine them. no one has been executed in the UK in over 50 years and we've had many laws in that time so I'm not really sure what your point is.