Your comment is partially correct, it is the Home Secretaries, past and present, who have been routinely told by the civil servants to tow the anti-encryption line, which goes back to RIPA 2000 and even further back. In essence it is GCHQ who are asking and they understand encryption perfectly well; since they can't ask directly, hence the role falls upon the relevant minister in government to do it.
This will once again become a hot-button issue as outlined in the Queen's speech. The Tory Party is also switching from Whatsapp to Signal ─ make of that, what you will.
https://www.theregister.co.uk/2017/07/10/former_gchq_wades_i...
https://www.theguardian.com/politics/2019/dec/17/tories-swit...