Laws are always enacted for specific reasons and purposes... many times quite commendable ones. The problem lies with human nature - people always look for "creative" ways to solve their own challenges or make their tasks easier. Hence bureaucrats often seek passage and enforcement of laws whose stated purpose may be entirely removed from the bureaucrat's sector of responsibility if it makes their job easier. E.g. those in the intelligence community may press for seemingly unrelated laws that will enhance their access, collection, and accumulation of data on all manner of citizen activity - foreign and domestic - since it enhances their ability to track intel targets or tease out threads of suspicious activity. Unfortunately, another human trait is that power corrupts them - and data about specific people converts immediately into power over them.
This sets up perpetual tension between freedom from government tyranny and proper governmental enforcement of civil order to protect society. The problem of human history is that once freedom has been lost to tyranny, it has been impossible to retrieve without bloodshed and civil chaos... hence the first priority of elected officials must always be to assure that laws they pass to protect society are crafted to prevent misuse that would erode the freedom of the citizenry... and if misuse is discovered, to revise those laws to block the misuse.
It's also for this reason that the US established its Constitution and Amendments, coupled with a strong judiciary, to preside over laws passed and enforced by other governmental arms and measure them against the Constitution, blocking those laws if necessary. Even so, with the passage of time, it can be argued there has been an erosion of citizenry freedom in the face of its ever-expanding government. In the UK, there is no specific written Constitution, but instead an elected Parliament that can define laws as it sees fit, though that fitness is normally constrained by 'rule of law', international law, and 'human rights' considerations.
This means there is no clear path of appeal for Apple and other encryption users against these UK laws, their potential misapplication, or their "unintended consequences" - apart from intervention by Parliament. Consequently, this is only likely to get worse before it gets better. The question will boil down to what the involved governmental agencies in the UK will attempt to do to Apple and others to force compliance - and what Apple and others will do in response.