I don't think they went through with it.

I remember reading a related article reclaimthenet

This same Home Office served Apple with a secret order, a Technical Capability Notice, demanding a backdoor into end-to-end encrypted iCloud backups, first for every human on the planet and later, after Washington threw a tantrum, for British users alone. Secret being the operative word, since the law gagged Apple from so much as admitting the order existed.

Apple’s answer was to rip its strongest encryption out of the UK entirely rather than build the thing, sniffing that it has “never built a backdoor or master key to any of our products or services,” and the fight is still grinding through the courts. That is the track record of this government, one that asks one company, in the dark, to dismantle encryption for an entire nation is not a government you hand a camera-side scanner and trust to use it gently.