The right to silence in England and Wales may cause for a guilty man to escape due to the privilege of silence in addition to the fact that a defendant does not have to prove his innocence.
However the rights were already well established by case law as was the necessity of no adverse comments, the principle being that the defendant does not have to prove his innocence  the burden of proof rests on the prosecution. It was a clear example of the privilege of silence having enabled a guilty man to escape." 
