When was the British Empire most powerful?

During the Victorian era, one quarter of the globe was under British rule. At the time, the British had the largest Empire in history, and England was the most powerful nation on Earth...

With regards to the BBC for the information.

Source Website : http://www.bbc.co.uk/dna/h2g2/A223002

Olmo1989: In terms of the amount of land the empire covered it was at its largest between the two world wars. After WW1 Britain occupied some of Germany and the Ottoman empires former territories, thus augmenting the empire's landmass and population. However, I would argue thought that by this point the British Empire was already past its strongest and was in decline. This decline began during the last 2 decades of the 19th century when other nations such as Germany, the USA and Russia began to industrialise and catch up with Britain economically. There was also increased imperial rivalry with Germany and France and increasingly Britain felt threatened by the emergence of other powers. From about 1815-1880 thought Britain pre-eminence in the world had been more or less unrivalled and she had pursued an isolationist policy.