Quote (last year) from the policy holder for RTF Phraseology for the UK.
“The UK has many differences with ICAO phraseology (actually section X of Doc 4444) and the UK has filed a general difference. We believe that the differences we have in the UK, which have been made as a result of experience over many years, have a safety benefit. However, we have no power over other states to change to our system.”
CAA (SRG) were looking at options to improve things as well.....