Long to reign over us! Queen, 96, reaches another incredible milestone as she becomes world's second longest-reigning monarch The Queen, 96, has become the world's second longest reigning monarch Reigned for 70 years and 126 days, the same as Bhumibol Adulyadej of Thailand She officially became the longest-reigning British monarch in September 2015 By HELEN ROBERTS FOR MAILONLINE PUBLISHED: 21:1..