Unfortunately, this means that mistakes are sometimes made - with innocent shoppers being "caught" shoplifting. Here, we explain how the law works and what you can do if you are falsely accused.
You can refuse to show him or her, but this could result in the police being called and the incident becoming much more serious than necessary.
What does the law say about shoplifting?
There is no specific law on shoplifting, or stealing from a shop. Instead, people who are found guilty of shoplifting are charged with theft under the Theft Act 1986.
If you are found guilty, the penalty will depend of the severity of the offence and whether you have been caught before. For a first-time offender, a fixed penalty of about £80 is common.
You may also receive a caution from the police, which can form part of a criminal record, or be asked by the shop concerned not to enter its walls for a certain period of time. Repeat offenders, on the other hand, risk jail time.
What are your rights if you are wrongly accused?
In-store security guards can ask to check the contents of your handbag, for example, if they suspect you of stealing.
You may be asked to show your receipt, or allow the guard to look in your bag, while you are within the store or once you have left it. Either way, the best approach is to remain calm and polite while stating your innocence.
You should agree to re-enter the store if you are outside, or to remain in the store if you are inside. However, it may be more sensible to remain in full view of other shoppers and staff, rather than agreeing to go into a separate room where you could more easily be intimidated.
If something has accidentally fallen into your bag, or you have honestly forgotten to pay for an item, one of the best ways to prove your innocence is to ask the store manager to check the relevant CCTV footage. Again, remaining calm should help.
What can you do if you are unable to prove your innocence?
Depending on the value of the item in question, and the shoplifting policy of the store, you may be allowed to leave without facing a fine or a formal police caution.
You may, however, be banned from shopping in the store in future, while your name may also be added a national database of incidents of dishonesty that can be accessed by prospective employers, for example.
You have a right to know if your name is being added to this database and what information will be held about you on it.
If the information has not be proven, is not relevant or does not relate to you, you also have the right to have it removed from the database. (Contact the Information Commissioner for more details.)
For more serious incidents that involve the police, your local Citizens Advice Bureau is a good first port of call.