I don't think TB is reffering to the format of the Daily Mirror, but rather to "tabloid" as in "a newspaper that tends to emphasize sensational crime stories, gossip columns repeating scandalous innuendos about the personal lives of celebrities and sports stars, and other so-called "junk food news"". I don't know much about the DM, but tabloids (in the meaning above, regardless of the format), are generally not very reliable. Perhaps this needs to be discussed at WP:RSN