The information in this blogpost may now be out of date. See the current GOV.UK content and publishing guidance.
We're bringing Inside Government content in line with mainstream on the use of 'quarter' or 'qtr' (when referring to a date range).
Please don't use this: it means different things to different departments (based on tax year, or calendar year) and assumes knowledge of the user that they may not have. Referring to the actual months removes any ambiguity and makes things clear for everyone.
This is mainly a problem in titles on transparency publications. Don't forget that you can use shortened versions of the names of the months on these, if you're pushed for space (see style guide, 2.7).
The style guide will be updated shortly with this change.