Is this fake news? Robert's first link dates back to 1988, in which a statutory instrument bans a whole bunch of manufactured weapons like knuckledusters, death stars, sword-sticks, butterfly knives, and hand-claws. Surely a good thing?
The blowpipe in question isn't a children's toy, or a random bit of copper pipe. It's the adult weapon. The boundary between toy and weapon isn't crystal clear. A pea-shooter propelling curare tipped darts is a lethal weapon, whereas a South American blowpipe loaded with peas isn't. And, as we know, it's not difficult to extemporise weapons, for example by weighting a stick with a stone. There are many ordinary domestic items that make good weapons. To deal with this, courts consider intent as well as possession.
Robert's second link is to the Offensive Weapons Act of 2019. It extends and clarifies, adding defences as well as tightening up on ownership. For example, it's a defence to own a sword for recognised religious or ceremonial purposes.
In the UK the Crown Prosecution Service test alleged offences and evidence before prosecuting to ensure the Court will take it seriously. Intent is important, and it can be challenged all the way back to the original: what did the government intend, what did MP's understand the intent to be, and did the police interpret the intent correctly?
Anyone expecting their home to be raided by Armed Police with a Warrant to look for illegal kiddie pea-shooters is in for a disappointment. Even more disappointed if a martyr to freedom expects his day in court and a heavy prison sentence.
Police raiding a home workshop manufacturing blow-pipes for sale to drug dealers from plumbing accessories is a different story!
The British system (Scots and English) has a series of checks and balances to protect citizens from misinterpreted and over-zealously applied law. Not perfect, but I'm not aware British prisons are overflowing with pensioners doing time for pea-shooter offences!
Dave