The major credit bureaus identify people with poor credit scores. Here are the major credit rating systems in the UK with their respective poor credit score limits:Experian (on a scale of 0 to 999) – a score lower than 720 is usually considered a bad credit score.Equifax (on a scale of 0 to 700) – a score lower than 379 is usually considered a bad credit score.TransUnion (on a scale of 0 to 710) – a score lower than 565 is usually considered a bad credit score.