During Queen Elizabeth's reign, did the British Empire become the largest empire the world had ever seen?

The British Empire did become the largest empire in world history, but its peak was actually during the reign of Queen Victoria in the 19th century, not Queen Elizabeth II in the 20th and 21st centuries. Victoria reigned from 1837 to 1901, a period of immense industrial and territorial expansion for Britain. By the end of her reign, the Empire covered roughly a quarter of the world's land surface and governed about a quarter of its population. Queen Elizabeth II, on the other hand, oversaw the dismantling of much of the Empire as former colonies gained independence. So, while Queen Elizabeth II is a significant figure in British history, the statement is false because the Empire's greatest extent occurred much earlier, during the Victorian era. It's easy to get confused because both are iconic queens, but remembering Victoria's long 19th-century reign helps place the Empire's peak in the correct historical period.
Think of Queen Victoria, not Elizabeth. The expansion of the empire peaked during Victoria's reign.