I assume you are referring to a credit rating that is used when applicants apply for financial products: loans, mortgages, credit cards etc. In the United Kingdom, some benefits and tax credits (social welfare) are being replaced by a new social security benefit called 'Universal Credit', and I assume you are not referring to this. There is also a Chinese company -- based in Hong Kong -- which is called the Universal Credit Rating Group (UCRG), but again, this company should not be confused with the answer to your question.
Not everyone will have a credit rating / credit profile. It is created when an individual first applies for a financial product in the UK, and is updated as that person uses the financial products they have been accepted for: current account, credit card, personal loan etc. Banks and the issuier of financial products (credit cards) -- in the UK -- use Credit Reference Agencies to build these credit ratings / profiles. Because banks tend to use three large Credit Reference Agencies -- Callcredit Limited, Equifax Limited and Experian Limited -- it may appear that there is a universal credit rating, because banks are getting their information from a select few sources. Credit Reference Agencies will source information from the following areas: past applications; court credit records; court fraud records; the electoral roll; and account transactions (defaults) from lenders. What should be noted, however, is that banks and financial companies only use the information provided by Credit Reference Agencies to help them make a decision, and they will use the information differently.
Therefore, whenever its been investigated, the conclusion has been that there is no such thing as a single universal credit rating / credit profile, but the information pool that is used by Credit Reference Agencies is similar, so it may appear that there is a universal credit rating. The reality is that each lender will individually determine how fit a borrower is for the product they are applying for. Likewise the idea of getting blacklisted also appears to be a myth. There are financial products for different types of borrowers, and there are products (credit building credit cards) that help consumers rebuild their credit rating/profile. If you are wondering what your credit profile/rating is, then there are websites -- such as noddle.co.uk, part of Callcredit -- that build a credit score based on similar methods that the Credit Reference Agencies use. The Noddle website perfectly sums up why there is not a universal credit rating "Theres no industry standard or one size fits all and thats why its often recommended to use more than one CRA when checking your credit score."
If you are wanting to build a better credit rating, then its recommended by the three large Credit Reference Agencies that you join the electoral register. The electoral register is used by CRAs to confirm an identity. Alongside that, paying bills on time, and using products specifically designed to rebuild a credit score, is a good base for a credit building strategy.