Hi,
I am a non EU citizen came in Portugal without valid visa about a month ago. My girl friend is British. She want to come and marry me in Portugal. Am I allowed to get married here? If yes after getting married can I allowed apply Portuguese citizen? How long it will take to apply? What is requirements to apply? Or can I apply for British citizen from here?
Some one please help me.
Many thanks,
Foysal.

If you are in Portugal without a valid visa, there is no way you will be able to apply for citizenship; you are non EU citizen, what country are you from. And no, you will not be able to apply for British citizenship.

What passport do you hold ?