<blockquote>The 28-year-old was held for nine hours, the maximum the law allows before officers must release or formally arrest the individual. According <a title="" href="https://www.gov.uk/government/uploads/system/uploads/attachment_data/file/157896/consultation-document.pdf">to official figures, most examinations under schedule 7 – over 97% – last less than an hour, and only one in 2,000 people detained are kept for more than six hours</a>.</blockquote>
via <a href="http://www.theguardian.com/world/2013/aug/18/glenn-greenwald-guardian-partner-detained-heathrow">Glenn Greenwald's partner detained at Heathrow airport for nine hours | World news | The Guardian</a>.