Obviously this free dissemination of uncensored news coupled with the fact that the un-moderated, anonymous open publishing model makes it nearly impossible for the collective that runs the site to be held legally liable for it's content means that Indymedia is hated by the British authorities and there have been various attempts to shut it down over the years. These efforts have included multiple police raids and illegal seizure (read theft) of computer equipment but most recently have focused on police officers serving with a dedicated unit known as the "National Extremism Tactical Co-ordination Unit (NECTU)" either posting articles calling for more moderation or articles that are so deeply offensive that they cause others to call for more moderation.
At around the time that all those undercover police officers were operating within the UK activist scene these calls for tighter moderation took hold among the Indymedia collective fuelled by the usual mix of paranoia, ego and passionately held political beliefs. Eventually this led to two distinct groups forming within the collective. One known as the Mayday collective wanted to keep Indymedia pretty much as it is while the other known as the BeTheMedia (BTM) collective wanted to shut down Indymedia completely and replace it with a tightly moderated, isolationist site that would focus on British news for British people. Bizarrely these two groups reached a consensus decision that on May 1st 2011 the UK Indymedia site would gradually be wound down and replaced by two new sites; Mayday and BeTheMedia.
When May 1st arrived the BTM group insisted that the Indymedia site be shutdown immediately. This went against the consensus decision so the Mayday group locked the BTM group out of the running of the site and kept it going. There is currently a three week suspension on the site shutdown to allow the factions to meet in person to try and solve their differences. I expect that the Indymedia site will remain open after that because if the BTM group want to go and do something different then the Internet is a big place so there's nothing stopping them and they don't need to shut down Indymedia to do it.