There’s an interesting report today about a letter, apparently leaked by the Liberal Democrats (not a rare occurrence, it turns out), sent by Sajid Javid to the Prime Minister about Theresa May’s anti-extremism proposals in March.

At the time, Javid was Culture Secretary, so May’s idea of empowering OfCom to pre-vet television programmes for possible extremist content came under his brief. He expressed concerns that the proposal would effectively make OfCom a censor rather than a regulator, and that there was a risk such powers could be used to control content that was not currently intended to be restricted.

It’s an insight into the now Business Secretary’s commitment to free speech – he’s surely right that liberty in the UK would not benefit from having a quango watch every television programme in advance in case it should be banned. I don’t know John Whittingdale’s stance on the specific policy, but as a long-standing advocate of media freedom I would be surprised if he didn’t share a similar concern.

But there’s another aspect – Javid’s letter warns of “the difficulty of defining extremism”. In doing so he gives a glimpse into the difficult maze that this Government and, belatedly, the last Labour Government must navigate in counter-extremism policy.

Incitement of violence or hatred is already forbidden. But it became clear as the growing prominence of Islamism developed in the first decade of this century that those definitions are not necessarily broad enough. By the time you have someone explicitly promoting criminal or violent acts, the majority of the road to extremism has already been trodden.

Those whom the Home Office is battling against are not stupid – there are a variety of well-advised figures who know exactly where the current legal lines lie and thus have become expert at avoiding crossing them. We’ve all seen and heard such talking heads, dancing carefully around the law while communicating what is still an extreme message – be it with regard to democracy, liberty or even the question of those British citizens who have traveled to join militant movements. It’s a battle between the slow pace, and technical difficulties, of the law and the nimbleness of some very committed people who in no way have our best interests at heart.

Javid’s intervention to the Prime Minister illustrates the ethical difficulties, but it also highlights that this is a legal minefield. Too broadly phrased and a law becomes damaging to the free speech of those who aren’t the intended targets. Too tightly phrased and people are still allowed to go on the air using weasel words to send messages that were meant to be forbidden.

We have come a long way in recent years – the days when the Blair Government misguidedly anointed deeply unrepresentative and often unpleasant organisations or individuals as supposedly legitimate ‘spokesmen’ for whole religions are behind us, and several of the most notorious hate preachers have since been deported or imprisoned (or both). Michael Gove will no doubt soon be addressing the ways in which the Human Rights Act has served to undermine just and reasonable decisions to deport other such criminals, for example. But as the Javid/May clash shows, there is no sign of the issues becoming any easier to navigate – and, as the then Culture Secretary effectively warned, we must continue to be incredibly careful, lest we destroy freedom in trying to protect it.