Metro is a free newspaper distributed on public transportation across the UK that was founded in 1999. It achieved a readership of over 1 million within five years, making it the fourth largest weekday newspaper in the UK. By 2010, Metro was printing approximately 1.3 million copies daily and had over 3.5 million readers. In recent years its circulation has continued to increase, surpassing The Sun as the largest weekday newspaper in the UK in 2017 with a circulation of nearly 1.5 million copies. As a free newspaper distributed on public transportation, Metro does not target a specific audience.