Your question has to dimension to take into consideration.
- handling multiple languages
- handling duplicates
Handling multiple languages
Organizing language versions in subdirectories is a good strategy. For me it is best practise.
If you are able to identify which language/country your user is looking for redirect him to the right directory.
If not - lead him to your global start page. That is fine so far.
If you visit www.example.com it will redirect you to either
www.example.com/uk or www.example.com/ie or www.example.com/global.
Handling multiple languages for different search engines:
Google and Yandex are using hreflang as a guide to multilanguage pages.
A sample configuration for your page may look like this:
<link rel="alternate" href="http://example.com/ie" hreflang="en-ie" />
<link rel="alternate" href="http://example.com/uk" hreflang="en-gb" />
<link rel="alternate" href="http://example.com/global" hreflang="x-default" />
Always make sure your hreflang is also self-referential!
Bing uses language meta-tags.
A sample configuration for example.com/uk may look like this:
<meta http-equiv=”content-language” content=”en-uk”>
You can check for language detection in the search engine's own web master tools:
Handling page duplicates
By always redirecting to one of your language directories you handle the duplicate
Make sure you are always using a
301 redirect. Then there is no problem for your homepage being redirected to a subdirectory. Depending on the location a web crawler visits your page it always is redirected to the right version of your page. Indexing the
example.com duplicate is omitted.
As you said:
This is OK, and incidentally is how The Guardian newspaper works.
If your web server accepts URLs that do not contain a language directory like
example.com/topics/article-01 make sure those get either redirected to their equivalent version (f.e
example.com/global/topics/article-01) or have a canonical link element pointing to their equivalent.