Lesson of History
When Station X systematically cracked Engima, they kept it quiet for around 25 years. During that period of time a Swiss company sold an updated Engima until the mid/late 1960's. All encrypted messages were decipherable.
In the early 1990s military grade encryption was 8196 bit PKI, in twenty + plus years we are still using 2048 bit encryption, cpu processing performance has improved but security standards have not.
A case in point while do all Firewalls come with some form of DES encryption, what is worse that someone people actually use it.
Just because the PM stands and wants encryption backdoors does not mean that GCHQ actually need them, the police might however.