Delivering the Scottish Council of Law Reporting’s Macfadyen Lecture 2017, entitled “Terrorism and the Rule of Law”, Sir Anthony Campbell PC charted the law’s development in response to ever-changing threats, from dynamite to drones.

In 1883 the government introduced the Explosive Substances Bill in response to dynamite bombings by the Irish Republican Brotherhood and, following the Birmingham Pub Bombings in November 1974, a temporary anti-terrorism bill was introduced by the Home Secretary of the day, Roy Jenkins.

Sir Anthony noted that “One problem with this type of legislation is that it is not always clear when the danger has passed”. He quoted Lord Jellicoe, who said in 1983 that the word “temporary” “rings increasingly hollow as the years go by”.

Compounding this is the fact “police and other security services applying the legislation become accustomed to it and there is unlikely to be any pressure from that influential quarter for change; especially if their powers are likely to be reduced or removed.”

Sir Anthony also pointed to the threat posed by drones: “If Amazon claims to be able to deliver packages weighing up to 5 lbs by drone, how easy will it be for a terrorist to deliver an explosive device or drop chemicals on a crowded football stadium by the same means?”

At present, the Air Navigation Order 2016 provides “limited protection against such an event” while the former head of GCHQ has warned that groups including so-called Islamic State “were looking at the technological advantages to them of cyber-attacks on the nation’s infrastructure”.

He added that “one can only imagine what would happen if air traffic control, power stations and hospitals were the subject of an attack” cautioning that “if society is to be protected from terrorism, it must be ready to respond to the danger of misuse that accompanies many of the advances being made in science, technology and other fields”.