Is the Price of Safety, Liberty?

Safety and Liberty are both key principles of a prosperous and liberal democracy, these ideas are often at odds with each other. Governments are perpetually having to strike a balance between the two.  

What institutions are in place to maintain this balance in the UK and how do they do so? 

To what extent should we allow either value to encroach on the other? 

How much Liberty can we give up for the safety of ourselves and others around us? 

Conversely, should Liberty be upheld no matter what the implications are for our safety?