At the time of the novel's publication the British Empire had conquered and colonised dozens of territories in Africa, Australia, North and South America, the Middle East, South and Southeast Asia, and the Atlantic and Pacific islands.

While Invasion Literature had provided an imaginative foundation for the idea of the heart of the British Empire being conquered by foreign forces, it was not until The War of the Worlds that the reading public was presented with an adversary completely superior to themselves.
A significant motivating force behind the success of the British Empire was its use of sophisticated technology; the Martians, also attempting to establish an empire on Earth, have technology superior to their British adversaries.
In The War of the Worlds, Wells depicted an imperial power as the victim of imperial aggression, and thus perhaps encouraging the reader to consider imperialism itself.

Wells suggests this idea in the following passage:
And before we judge them [the Martians] too harshly, we must remember what ruthless and utter destruction our own species has wrought, not only upon animals, such as the vanished Bison and the Dodo, but upon its own inferior races.
The Tasmanians, in spite of their human likeness, were entirely swept out of existence in a war of extermination waged by European immigrants, in the space of fifty years.
Are we such apostles of mercy as to complain if the Martians warred in the same spirit?

— Chapter I, "The Eve of the War"
At the time of the novel's publication the British Empire had conquered and colonised dozens of territories in Africa, Australia, North and South America, the Middle East, South and Southeast Asia, and the Atlantic and Pacific islands.
While Invasion Literature had provided an imaginative foundation for the idea of the heart of the British Empire being conquered by foreign forces, it was not until The War of the Worlds that the reading public was presented with an adversary completely superior to themselves. A significant motivating force behind the success of the British Empire was its use of sophisticated technology; the Martians, also attempting to establish an empire on Earth, have technology superior to their British adversaries. In The War of the Worlds, Wells depicted an imperial power as the victim of imperial aggression, and thus perhaps encouraging the reader to consider imperialism itself.
Wells suggests this idea in the following passage:
And before we judge them [the Martians] too harshly, we must remember what ruthless and utter destruction our own species has wrought, not only upon animals, such as the vanished Bison and the Dodo, but upon its own inferior races. The Tasmanians, in spite of their human likeness, were entirely swept out of existence in a war of extermination waged by European immigrants, in the space of fifty years. Are we such apostles of mercy as to complain if the Martians warred in the same spirit?
— Chapter I, "The Eve of the War"
The War of the Worlds