If they really do plan to ban encryption, the response will be much faster than retail. There is literally no way London financial business can safely exist without encryption. Investments, accounts, insurances, etc. pretty much require encryption under the current DPA and any comparable law of other countries.

The moment London banks say "we're forced to use backdoored/no encryption", any foreign business they interact with will (have to) say "LOL, bye then".

Majority of tech companies are not even comparable to that market.