It's not just the UK, it's been that way here in the states for a few months now. I was emailed about a couple of videos that I had published to youtube back a couple of months ago and they told me that they had been disabled because of music infringement rights and that I could try using different music or use some of their music that they would furnish.
A lot of the artists music are still available on youtube though. It was mostly all about the "Warner Music" rights that they pulled.
What a joke, this is RETROACTIVE. The rights WERE there when the content was used, and users should expect to be able to keep relevant content available once they have agreements (or "fair use") permissions for any content owned by another entity.
From being too lax, YouTube have now gone too far the other way, and this is effectively censoring the internet. In this case, censoring a Meister webcast because of a bit of background music at the end that used to be OK.
Are loads of users being told their videos are now deemed "disabled" till they edit them to the new standards, and who is to say the goalposts will not shift again, and they are asked to edit them yet again.
If YouTube ceases to function effectively because of an overload of disabling, then it will stop being the default choice for uploaded content, and copyright holders may well find that a new upstart has taken over, who will simply refuse to enforce any kind of copyright rule and tell them it's back to the days of them having to find it, complain, have it investigated, and then removed - doing this separately for each offending clip.
I recently found the site hit40UK has effectively ceased to function because virtually ALL their embedded youtube content has been "disabled" to some extent. I now know what has been going on. hit40UK, when working, is actually a site designed to SELL the damn music by allowing you to see the chart, verify a track with a clip, or even the promotional video, and then send you on your way with enough info to buy the track.