With border officials detaining the partner of an investigative journalist at Heathrow for nine hours, and the arrest of 25 anti-fracking protesters at Balcombe, there is renewed debate over the balance between state power and personal freedom in Britain.

One of Britain's foremost thinkers on freedom, John Stuart Mill, argued in 1859 that we should adopt the 'harm to others' principle - curtailing state interference with the exercise freedom, unless it hurts, harms of interferes with others' enjoyment of their freedoms. I have written a column for the Daily Telegraph tomorrow, applying Mill's test to the Miranda case and the arrests in Balcombe. You can read the column here.