Typically you won’t be approved for a credit card if you have a poor credit history or don’t meet the above eligibility criteria. If you’ve got an outstanding CCJ or are on an individual voluntary arrangement (IVA) it is also likely you will not be approved.
Equally, if you do not have a credit record at all, you may be turned down. It is advisable to go to Experian, or another credit rating agency, and to ask for a credit report.