THE Queen has become Britain's oldest ever monarch today, reaching a new milestone in a job she has held for more than half a century.

The Queen, now 81, has passed the mark set by her great-great-grandmother, Queen Victoria.

Her son, Prince Charles, is also closing in on the title of longest-waiting heir to the throne.

Victoria was born on May 24, 1819, and lived for 81 years and 243 days.

The Queen, who took the throne in 1952, is one of only five kings or queens since the 1066 Norman Conquest to reign for more than half a century.

On September 9, 2015, she will pass Queen Victoria, who ruled for almost 64 years, as the longest-reigning monarch.

The Queen may have many years left in the job.

Her mother, the Queen Mother Elizabeth, died in 2002 at the age of 101.