The quality of debate here has been pretty poor, and a number of tired arguments have been pulled out. In the UK the non-white, non-EU/American/Commonwealth population is poorer and more disadvantaged than the majority. As a result, they are statistically more likely to commit crimes. Equally, however, they are statistically more likely to be suspected of crime, and statistically more likley to be suspected than their white counterparts of the same class. Whilst fare dodging as a crime doesn't map as closely to economic and social status as some other crimes, there is still a statistical link.
The point is that a mixture of statistical reasoning and cultural basis, at times appearing racist, is going on. Anyone who says that they are never prejudiced is lying. We all pre-judge people, to a greater or lesser extent. the problem comes where these prejudices lead to different treatment of people eg performing more stringent ticket checks on black people, or believing the excuses of an elderly white woman who has forgotten a senior railcard more readily than a black teenager who has forgotten a YP, purely through demographic profiling