Has this site been blacklisted

When I type in site:adomain.co.uk there is a listing of the site’s pages. However, when I type in link:adomain.co.uk the page is blank.
adomain.co.uk is the site I am checking.

Does this mean that the site is blacklisted?

I should have said that previously link:adomain.co.uk revealed dozens of results

Ignore the link: operator. It provides meaningless results.

But why would it suddenly start showing no results?

No idea, but as its a meaningless search, spend your time worrying about something else.

This isn’t an isolated problem - the site has also dropped out of the sky for all but 1 search term in the past week or so
I suspect that automated backlinking was used previously.

No, what it means is that Google doesn’t actually give you anything useful with the link: operator any more (and hasn’t done for a little while). Whether it was partly a security measure, or wholly a way to drive people towards Google Webmaster Tools I’m not sure, but doing a link: search rarely gives many results, if any. GWT should give you the full list.