This is an official site, run by West Yorkshire Police on behalf of the Police National Legal Database:
https://www.askthe.police.uk/view-category/?id=01bf981b-6ad2-eb11-bacb-000d3ad57443
Click on 'Is it an offence not to carry all relevant documents . . . ' to find information goes some way towards answering your question, Barry.
As that link indicates, the relevant legislation (s.164, Road Traffic Act 1988) remains in place. However, as other have indicated, the need for it to actually be used has been greatly reduced by advances in technology, such as ANPR cameras, immediate roadside access to the insurance database and so on.
As has been pointed out though, actually reporting to a police station is now often far from easy. Here in Suffolk, there are just three police stations open to the public across the whole of the county and with those stations only open from 9 until 5, Monday to Saturday.