Yesterday, Jo Johnson told the National Union of Students to drop its opposition to the Prevent counter-terrorism strategy, saying that the programme was ¡°not about oppressing free speech or stifling academic freedom, it is about making sure that radical views and ideas are not given the oxygen they need to flourish¡±.?

In other words, you could say, it is about stopping certain people saying certain things. If that meant stopping hate speech, or incitement, it could be lauded - but Prevent is too blunt an instrument to achieve that. Its operation in universities will see debate stifled, muted, distorted or stopped altogether.?

But free speech is the crucible in which to assay ideas. ¡°Sunlight is said to be the best of disinfectants,¡± said former US? Supreme Court justice Louis Dembitz Brandeis. Prevent will force dangerous minds into the shadows.

Universities are gearing up with policies, training and monitoring in order to discharge their general duty to ¡°have due regard to the need to prevent people from being drawn into terrorism¡±. They are less prepared for the legal troubles that will follow.

³ÉÈËVRÊÓƵ

Lecturers will be obliged to report students at risk of ¡°radicalisation¡±, a portmanteau term susceptible to glib stereotyping, and fear of radical ideas themselves. If a lecturer refuses to follow policies and make reports, is that a disciplinary matter? Is a Muslim student taking too much interest in cryptography to be reported? Is it possible at all to be trained to reliably spot the signs of someone at risk of being drawn into terrorism ¨C or isn't that the province of the security services??

It is an odd duty indeed for an academic to bear.

Prevent modifies and curtails basic rights. That¡¯s not new ¨C the legitimate curtailment of freedoms is an essential part of the balancing of those rights. But Prevent seems to be aimed at the wrong targets, and its clumsy deadening hand will breach those rights unacceptably and unlawfully.

³ÉÈËVRÊÓƵ

If ¡°hard cases make bad law¡±, then this bad law will make hard cases too ¨C and plenty of them.

Phil Lindan is an associate and Meriel Schindler is a partner at law firm Withers LLP.