To what extent can the judiciary protect individual rights and liberties?

In wake of the Brexit fallout, this question is particularly unclear at present, as changes to our relationship with the European courts reamin undecided. However, looking at just the national level there are some conclusions we can draw, even if they are not definitive. 

One of the most important of these is the concept of 'Rule of Law' - a fundamental concept of the British (unwritten) constitution. This holds that in the UK, individuals are equal before the law, have the right to a fair trial, and can only be punished for illegal acts. This act as important protections against state encroachment on individual rights and liberties. This seems to protect individuals from institutional racism or prejudice, and ensures that every single person, regardless of the nature of their crime, is entitled to certain provisions in their court cases - for example, legal representation. 

However, the evidence in the UK does not always support this. For example, there is a vastly disproportionate number of ethnic minorities in prison, which many people have put down to the institutional racism of both the police and judges. Indeed, judges themselves come from very narrow backgrounds - in 2014, 71% of judges were privately educated, only 5% are from minority backgrounds, and they are predominantly male. As such, whilst the law holds that they should protect individuals equally, they may carry particular world views or prejudices as a result of their backgrounds which may contribute to why ethnic minorities are far more likely to be convicted. This suggests individuals are not protected, as being from a particular background can increase your chance of being arrested and imprisoned.