Business owners should be allowed to have weapons on their premises for protection. Shopkeepers are often victims of violent crimes like armed robbery. Many times law enforcement is not able to respond to these crimes in time to catch the criminals. Therefore, business owners need a way to defend themselves against these crimes.
Shopkeepers and business owners are more likely to be the victim of armed robbery than are ordinary citizens, so it makes sense that they should have some kind of firearm on hand for protection. However, they shouldn't just be handed out freely; anyone wishing to possess a firearm should be required to undergo certification and training so they understand not only how to use a firearm, but the dangers of having on in the first place, including the possibility that it might be taken from them and used during the committing of a crime.
If the U.K. started allowing shopkeepers to carry guns for protection it would cultivate a culture of violence. The United States is a perfect example of a country where violence is king and killings by guns are causing people to fear for their lives on a day to day basis.
No, business owners should not be allowed to have weapons on the premises. In my opinion the risk of having a weapon on the premises is far greater than not having one. All employees would need to be trusted and trained. The weapon would need to be readily accessible in case of an emergency and that creates an environment of fear.