<page_title> List of metro systems </page_title> <section_title> List </section_title> <table> <cell> London Underground <col_header> Name </col_header> </cell> <cell> 402 km (250 mi) <col_header> System length </col_header> </cell> </table>
London Underground has a total length of 402 kilometres (250 mi), making it the fourth longest metro system in the world.