What is the meaning of the phrase "as a last resort"?

As a last resort (idiom): 
English Meaning - If all other methods fail. 
Bangla Meaning - শেষ অবলম্বন।

Example Sentences: 
- British police are supposed to use guns only as a last resort.
- As a last resort, the stranded hikers decided to signal for help by lighting a fire.

Source: Cambridge Dictionary.