If you are applying for a loan or a credit card, then the lender will always check your credit records before deciding whether to give you the loan or not. These are not kept by the lenders themselves – instead, they pass on information about their transactions to credit agencies, which are independent of the lenders. You can find out your credit history and receive an independent credit rating for free at Experian.co.uk.
This information is compiled by the various agencies into a personal credit record, which is a list of every credit-related transaction carried out by that person. If they take out a loan or subscription of any kind, such as a credit card or a mobile phone contract, this will be recorded in the credit record, and all payments (missed or otherwise) will also be recorded.
These credit records do not give an absolute credit score, as each lender does its own scoring based on their own criteria. Two lenders could look at the same credit record with regard to the same size of loan, and make entirely different judgements. While missed payments and defaults can count against you when applying for a loan, a long history of loan payments, immaculate or not, is more reassuring to lenders than a record that shows that somebody has never borrowed money before.
This is why somebody who has a few missed payments in their record is more likely to be approved for a large loan, such as a mortgage, than somebody who has never had to make a loan or subscription payment in their life. If you have any defaults on your record, then the damage to your credit record can be repaired to a certain extent by entering arrangements with creditors to pay the money back, and establishing a long, unbroken record of loan repayments.
This is why it can pay to have a look at your credit report, so that you see what action you have to take in order to repair your credit rating. For more information about credit history, take a look at this Wikipedia page.