There is no such thing as an actual blacklist for credit, although there are some circumstances in which you will not be able to get credit from any lender.
Each lender will have their own criteria and therefore the ‘perfect’ customer will vary from lender to lender. For example, some lenders will specialise in offering credit to those with poor credit history rather than those with a high Credit Score.
All lenders are legally prohibited from lending to anyone that has been declared bankrupt within 12 months, during this time you will be unable to take out any credit. You may find however that whilst you can apply for credit after this period, it may be more difficult to get accepted.
There are also other factors that could prevent you from obtaining credit such as a new County Court Judgement. These are visible on your record for 6 years unless you can pay it off within 1 month and most lenders will not lend to you if they see this on your file. However, they are not prohibited from doing so and it will be at the lenders discretion.