If you request a credit limit increase, your lender will normally look at both your payment history with them and your general credit history. So if you have a poor credit history (usually recorded for at least 3 years with all lenders), you will score poorly. To find out how your credit profile looks, write to both Experian and Equifax (�2 fee) for your credit history. Note that this does not give you any kind of credit score, only your raw credit data. It is almost impossible to find out how lenders score you on the basis of this information, they have their own systems.