What is the official name of the clock tower in London that houses the bell called Big Ben?

The official name of the London clock tower that houses the bell called Big Ben is Elizabeth Tower.

The tower stands at the north end of the Palace of Westminster beside the River Thames. It was designed by Charles Barry and Augustus Pugin as part of the rebuilding of Parliament after the old palace was largely destroyed by fire in 1834. Construction began in 1843, and the tower was completed in 1859 in the Gothic Revival style.

The name Elizabeth Tower was adopted in 2012 to mark Queen Elizabeth II’s Diamond Jubilee. Before then, the structure was officially called the Clock Tower. Big Ben is technically the nickname of the Great Bell inside the tower, although everyday speech often uses “Big Ben” for the entire landmark.

The Great Bell weighs about 13.5 long tons and strikes the hour, while four smaller quarter bells chime the quarter hours. St. Stephen’s Tower is a different tower within the parliamentary complex, making it an unsuitable answer.