The May Queen

The hat–box was gone, and about six o'clock Ukridge appeared, so beaming and effervescent that I understood what had happened before he spoke. 'Corky, my boy', he said, vehemently, 'this is the maddest, merriest day of all the glad New Year, and you can quote me as saying so!'

Ukridge, 10 Ukridge Rounds a Nasty Corner

This reference comes from the Annotations compiled in Madame Eulalie's site 

'You seem to be approving of everything and everybody this morning.'

'I am. This is the maddest, merriest day of all the glad New Year, and you can quote me as saying so. Now then, what is it to be?'

Sam the Sudden, 18 Discussion at a Luncheon–Table

This reference comes from the Annotations compiled in Madame Eulalie's site 

He appeared to be under the impression that this was the maddest, merriest day of all the glad new year – a view in which he was vastly mistaken.

Laughing Gas, Chapter 13

This reference comes from the Annotations compiled in Madame Eulalie's site