The selling, marketing, and distribution of cryptocurrency-related derivatives and ETNs (exchange-traded notes) to retail investors is a contentious topic among UK policymakers.

The FCA vs The RPC , this is the reason 

     The Financial Conduct Authority (FCA) is in favour of banning the crypto industry in order to create economic control, while the Regulatory Policy Committee (RPC) considers such restrictions inappropriate for economic growth.

The FCA is the UK's financial regulatory body, and the RPC is an advisory body. Both work independently of government control.

Both being government agencies, the dispute between the two has caused uncertainty in policymaking on crypto in the UK. And as it should be, crypto haters side with the FCA, but crypto supporters side with the RCA.