There's just one problem with that approach: Windows XP. That's because Internet Explorer 8 is the latest version that XP can run.
Microsoft will officially stop supporting Windows XP on April 8th, but that doesn't mean that nobody is still using it. February 2014 figures from StatCounter estimate that around 10% of Irish PCs are still running XP. In fact the Irish Government had to make a €3 million deal with Microsoft for 12 months additional support.
Not all Windows XP users would use Internet Explorer of course. Even some traditional IE users would likely have switched to an alternative browser by now, because some major websites, e.g. Gmail, haven't worked properly in IE8 for some time.
StatCounter's estimate of IE8 usage in Ireland for March 2014 is just under 5%, but they report that IE8 is still the 2nd most popular version of Internet Explorer (after IE11 at 9.5%), because Microsoft introduced automatic version updates from IE9 onwards.
In our own work, we have come across several end clients still using IE8, including both local government and large corporate organisations.
So, if you are building a website for a broad Irish audience, it's still advisable to bear IE8 in mind for now, and ensure your client is clear about the extent to which you will support it.