Marrying an algerian legality

Hello I have a question,  I have a algerian husband (6 years younger than me) I am UK citizen we had only an orfi marriage with, no papers or anything registered. He is a visa over stayer,  I want to register the marriage in UK I'm I able to do that? Also if we have children will they automatically  assume algerian and British dual nationality under algerian law? Or is that only if the father was legally married to the mother under algerian law? What would be the legal status of the child in algeria if he is born to a algerian father and British mother overseas without their marriage being legal anywhere In the world ? What would the implications be culturally? Would the child be considered illegitimate under algerian law. I ask as my husband wants to have  a child with only an orfi  islamic ceromony only) marriage done in the UK.

Thanks