"The Firearms Act of 1920 was just a licensing law; the Harrison Narcotics Act was just a prescription system; and the serpent only asked Eve to eat an apple"

In a beautiful essay, Professor Joseph E. Olson and Professor David B. Kopel talk about how a fundamental freedom became an illegal action in a single century.

With gun ownership for self-protection now completely illegal (unless one works for the government), Britons have begun switching to other forms of protection. The government considers this an intolerable affront. Having, through administrative interpretation, delegitimized gun ownership for self-defense, the British government has been able to outlaw a variety of defensive items. For example, non-lethal chemical defense sprays, such as Mace, are now illegal in Britain, as are electric stun devices.

Some Britons are turning to guard dogs. Unfortunately dogs, unlike guns and knives, have a will of their own and sometimes attack innocent people on their own volition. The number of people injured by dogs has been rising, and the press is calling for bans on Rottweilers, Dobermans, and other "devil dogs." Under 1991 legislation, all pit bulls must be neutered or euthanized.

Other citizens choose to protect themselves with knives, but carrying a knife for defensive protection is considered illegal possession of an offensive weapon. One American tourist learned about this Orwellian offensive weapon law the hard way. After she used a pen knife to stab some men who were attacking her, a British court convicted her of carrying an offensive weapon. Her intention to use the pen knife for lawful defensive purposes converted the pen knife, under British legal newspeak, into an illegal "offensive weapon." In 1996, knife-carrying was made presumptively illegal, even without the "offensive" intent to use the weapon defensively. A person accused of the crime is allowed "to prove that he had a good reason or lawful authority for having" the knife when he did.

Early one evening in March 1987, Eric Butler, a fifty-six-year-old executive with B.P. Chemicals, was attacked while riding the London subway. Two men came after Butler and, as one witness described, began "strangling him and smashing his head against the door; his face was red and his eyes were popping out." No passenger on the subway moved to help him. "My air supply was being cut off," Butler later testified, "my eyes became blurred and I feared for my life." Concealed inside Butler's walking stick was a three-foot blade. Butler unsheathed the blade; "I lunged at the man wildly with my swordstick. I resorted to it as my last means of defense." He stabbed an attacker's stomach. The attackers were charged with unlawful wounding. Butler was tried and convicted of carrying an offensive weapon. The court gave him a suspended sentence, but denounced the "breach of the law which has become so prevalent in London in recent months that one has to look for a deterrent." Butler's self-defense was the only known instance of use of a swordstick in a "crime." Home Secretary Douglas Hurd, using powers granted under the 1988 Criminal Justice Act, immediately outlawed possession of swordsticks. The Act has also been used to ban blowpipes and other exotica which, while hardly a crime problem, were determined by the Home Secretary not be the sorts of things which he thought any Briton could have a good reason to possess.

No prosecution for defending oneself is too absurd.
While the essay is primarily regarding firearms restrictions, it's worth noting that the slippery slope applies to all rights, even as it appears some are being strengthened. Jury rights (long since lost in Alberta, one notes), speech rights (under constant attack), even freedom of association flies at the merest nudge from SJWs on Supreme and Appellate Courts.

It's worth then noting that the first of the "seven key factors" in the loss of British gun rights was...
The first factor that undermined the British right to arms was a technological change when revolvers came to be seen by some persons as much more dangerous than previous weapons. This same phenomenon can be seen in the treatment of other technological advances, such as the automobile, which from the 1920s onward, has often been treated by the United States Supreme Court as a "Constitution-free zone", where searches and seizures in contravention of normal Fourth Amendment standards may take place.
Indeed, thanks to the web free speech is now considered so "dangerous" that it can be trampled upon (almost) with impunity. Likewise...
The shifting of the burden of proof, both at law and in popular discussion, was the fourth factor degrading the British right to arms. Rather than the government having to prove that a particular gun-owner or a particular type of gun was dangerous, the gun-owner began to have to prove his "good reason," and the government began deciding to outlaw weapons that the government did not think anyone outside the government had a good reason to own.
One recalls that when "Fuck Her Right in the Pussy" was a major issue, the far-left CBC that has no problem demanding tax dollars to fund its political communication while saying YOURS is "hurtful" and has "no good reason" to exist.

And as for the government banning the truth about the sick Sodomite Agenda, look at the sixth factor...
Additionally, how many people are there who care to resist infringement of a right? Few politicians seriously propose a total gun ban in the United States because there are seventy million gun-owning households--about half the population. But only about four percent of the British population legally owns guns--a much smaller interest group. If, over the course of generations, the percentage of a population that is interested in a right can be gradually reduced, stricter controls become more politically feasible, and the stricter controls can further reduce the long-term number of people who exercise their rights.

This suggests the long-term importance of young people exercising their rights. If high school newspapers have large staffs that fearlessly report the truth, the future of the First Amendment is better protected. If, conversely, laws prevent teenagers from target shooting or hunting, the future of the Second Amendment is endangered.
No wonder the huge push for Faggot-Familiar-Alliances in Alberta schools!

The essay is particularly vicious on the favourite topic of the left: "balancing" rights.
The rhetoric of balancing is dangerous because it tends to give too much weight to the short-term concerns of public safety. Thus, the American right that has been most subject to balancing, the Fourth Amendment, has suffered badly in the United States Supreme Court. More fundamentally, the "balancing" that legislatures or courts sometimes do is not their job, because the balancing has already been done. Whether in the 1689 Bill of Rights, which was to apply "for all time," or in the 1789-91 United States Constitution, a balance was struck. Because of this balance, governments were prohibited from doing certain things since, in the long run, public safety and liberty were both enhanced by preventing short-term considerations from controlling. Thus, when the Blaisdell Court "balanced" its way around the Constitution's absolute ban on the impairment of contracts, and upheld Minnesota's debtor relief law, the Court did not merely err--the Court usurped power and attempted to re-open the question that the Contracts Clause had decided with finality.

When rights are protected with bright lines, as the First Amendment usually is, then rights are particularly secure against slippery slopes. When rights are subjected to "balancing" (a/k/a "reasonableness") tests by courts, as the Fifth Amendment Takings Clause often is, then rights are particularly vulnerable. And when a society has lost the theory of constitutional absolutes as Britain has, and replaced this with "balancing," then every right is in danger.

In this way, the essay unintentionally but notably takes aim with the NRA. The NRA, one notes, in an implicit "balancing" organization that says strict adherence to existing gun laws should be performed, but oppose (most) new ones...until passed. And then they are to be strictly enforced. In a way, the gun owners' biggest and most effective lobby is also subtly and slowly disenfranchising them.
The BASC's stance may appear to be a "reasonable" position, which demonstrates that gun-owners are not bloodthirsty nuts wanting to shoot people. Rather, shooters are harmless sportsmen, and licensed guns belong in the same category as cricket bats or golf clubs. In practice, however, the concession that guns are only for sports undermines defense of the right to bear arms. If guns are not to be owned for defense, then guns make no positive contribution to public safety. If the sovereignty of the central government is absolute, then the people's ownership of arms makes no positive contribution to a sound body politic.

Their final paragraph is awfully important. Please read it twice.
Slippery slopes are not inevitable, but neither are they imaginary. The British experience demonstrates that many civil liberties, including the right to arms, really can slowly slide all the way to the bottom of the slippery slope. While we have not aimed to convince readers to value any particular civil liberty, such as arms, speech, or protection from warrantless searches, we have attempted to show that it is reasonable for groups that do honor such rights, like the NRA, ACLU, or NACDL, to refuse to acquiesce in "reasonable" infringements of those rights. Even though, as John Maynard Keynes observed, we are all dead in the long run, persons who cherish a particular civil liberty want that liberty to endure not just in their own lifetimes, but in the lives of subsequent generations. In the long run, the best way to protect a given civil liberty from destruction may be to resist even the smallest infringements in short run.

Hear hear.