Why was England so powerful?

England became so powerful because of the following reasons:

• England had a powerful navy that outlassed most of its European rivals in terms of firepower and maneuverability.
  

• Its colonies gave it the economic power needed to maintain a large standing army.

• Technological advances during the Industrial revolution made it possible for England to have a qualitative edge over its European rivals

For further reading check the following articles:

• Industrial Revolution
• British Raj
• European Colonialism