Cyber attacks have become a familiar, if depressing, feature of modern corporate life. For the most part they are small in scale and motivated principally by money. Their main implication is to administer a wake-up call to the IT department. Stronger firewalls are erected; the world moves on.

But the assault on Sony Pictures falls into an entirely different — and more worrying — category. In recent weeks, the company has been targeted by hackers seeking not cash but the withdrawal of a film called The Interview, which depicts the assassination of North Korean leader Kim Jong Un. To bend Sony to their will, they have released immense quantities of information about the company across the web, including private emails, film scripts and personal accounts.

Sony has now buckled. The company has withdrawn the movie from general release. The pressure on it may have been relentless but the precedent is troubling. When a group of anonymous hackers can force a major corporation to abandon a costly artistic project, it raises serious questions about self-censorship and the freedom of expression.