CEP Senior Advisor Ian Acheson writes: The last time I visited HMP Frankland, where three prison officers were reportedly attacked and seriously injured by a terrorist yesterday, was in 2015. Then, I had been tasked by the government to investigate Islamist extremism in the prison system. The best way of knowing what is happening on the front line, far from the HQ bureaucrats’ reach, is to go there. And so I visited every high-security prison holding extremists – including Frankland, just outside Durham – to ask staff how they kept safe and what more they needed. I can still remember the chilling ordinariness of men and women in uniform explaining how they worked to avoid being taken hostage and murdered by dangerous ideologues who viewed them as available targets for jihad. One officer said that the only thing that kept him safe each day was not his employer but “sheer blind luck”.