"you have the right to remain silent"
Who told you you have it in the UK?
UK does not have fundamental rights and more specifically presumption of innocence and right to not self-incriminate.
It is a side effect of UK being the only other country besides Saudi Arabia which does not have a proper written constitution. Parliament is sovereign and shall not be bound. As a result when the governing party decides to sneak yet another erosion of rights into law books there is nothing there to stop it except the EUCHR and EUHR convention. You now know why Josephina Vissarionovna May is so desperate to get us out of it. By the way, a UK Bill of Rights is not a replacement, because it will be amended and eroded the same way the original Bill of Rights was amended over the years. Via "Parliament is Sovereign and shall not be bound".