When did the UK stop using full stops in abbreviations and acronyms?

Question

I have noticed that in older (usually over 30 or 40 years old) British books and newspapers, abbreviations are without exception typeset with in full stops, as is still the practice in the United States. Yet, virtually without exception, modern publications typeset all the abbreviations without full stops. So, for example, in an old text one might see:

Marshall Hall K.C. — U.K . — Walsh v. Lonsdale — James Maxwell F.R.S.

Whereas virtually all modern British publications would write:

Marshall Hall KC — UK — Walsh v Lonsdale — James Maxwell FRS

When and why did this change happen? As best I can tell, it was sometime in the 20th century, but I have yet to find details on the change in style.

Answer 1

As Michael Harvey says, this is a trend, and indeed the American Heritage Abbreviations Dictionary says so:

Abbreviations vary widely in their style of punctuations, ... Following the contemporary trend toward less frequent use of periods, entries in The American Heritage Abbreviations Dictionary, Second Edition, are generally shown without periods, except for truncations and terms that require or almost always appear with punctuation.

This journal article from 1989 suggests that periods get dropped from abbreviations when they become commonly used as words:

The fact that a given abbreviation or acronym is spelled more often today without periods than with them suggests that it is now a more direct part of the vocabulary.

From Cannon, G. (1989). Abbreviations and Acronyms in English Word-Formation. American Speech, 64(2), 99. doi:10.2307/455038 (page 11)

Note, therefore, that this trend is not necessarily restricted to the UK!