Is Labour Starting To Abolish Democracy...
News10 mins ago
No best answer has yet been selected by hotrocker. Once a best answer has been selected, it will be shown here.
For more on marking an answer as the "Best Answer", please visit our FAQ.I have found a website giving the answer as 1978. As it provides no details, I leave it to you to judge the accuracy of the information.
http://www.peak.org/~jeremy/dictionary/tables/holidays_uk.php
The DTI gives some more information here.
The DTI site seems to give the impression that it wasn't made a bank holiday in Scotland in 1978, so as the question refers to the "whole of the UK", I'm still undecided.
The 2nd paragraph in the following link refers to 1975. http://www.cpgb.org.uk/worker/478/rewinning.html
From here "In 1978, the first Monday in May in England, Wales and Northern Ireland, and the last Monday in May in Scotland, became additional bank holidays. (The first Monday in May was already a Bank Holiday in Scotland..... )"
So if it were me, I'd say 1978 is the answer