Census not so confidential?

I always believed that census data genuinely was inaccessible to anyone outside the ONS - until now. This article

http://www.rssenews.org.uk/articles/20100903

and this expansion

http://www.straightstatistics.org/article/2011-census-how-private

suggest that the ONS could be obliged by the 2007 Statistics and Registration Act, clause 39, to pass on your details to the police and MI5.