I got a question for you: This is a list of countries and territories with a flag that incorporates the Union Jack. Six Commonwealth nations have the Union Jack on their national flag. The first Commonwealth country to drop the Union Jack was Canada in 1965, after adopting a new national flag. The most recent country to drop the Union Jack from its flag was South Africa in 1994, after adopting a new national flag. The only overseas territory without the Union Jack on its current flag is Gibraltar.

Based on this passage, how many flags have the british flag on them?
Let's think first:
The relevant information to answer the above question is: Six Commonwealth nations have the Union Jack on their national flag.
Therefore, the answer is Six Commonwealth nations.