I have a relationship with a Muslimah from England and I want to marry her. But I don't have relation with her family. Can I tell her about my idea or no? Or I must tell her family and how?

All perfect praise be to Allah, The Lord of the Worlds. I testify that there is none worthy of worship except Allah, and that Muhammad is His slave and Messenger.

If the woman is a virgin, she should be engaged via her “Wali” (her guardian, father or someone else from her family), just like the Prophet became engaged to ‘Aa’ishah and her guardian was her father Abu Bakr .

If the woman has reached maturity, she is allowed to engage herself without the guardian, but there must be a mediator between the man and the woman, taking care that engagement by herself will not lead them to some evil deeds, such as being in seclusion that can drag them to disgraceful results. This is regarding the engagement.

Considering the marriage, there is an obligatory condition. The woman must have a “Wali”; he is her guardian who performs the marriage procedure. It is not permitted for the woman to marry without a guardian. The Prophet said: “There is no marriage except with a ‘Wali’ (woman's guardian) and two just witnesses.”

As we understand the questioner's question, we see that he has a relationship with this woman before the marriage. This kind of relationship is strictly forbidden. It is his (her) duty to cut this kind of relationship immediately because Allah Almighty Ordered to lower the gaze. It is also forbidden for the woman to talk to a non-Mahram man with yielding and soft voice which can be the reason to draw his thoughts into the unlawful. Allah Ordered the woman to cover herself in front of non-Mahram people.

The questioner has transgressed all these orders and prohibitions with this woman. He should fear Allah and stop these actions. The woman should ask her guardian to marry her with you, and for sure Allah Almighty will give you lot of goodness in following His lawful Rulings.

Allah knows best.