Citizenship after divorce - Surinder Singh

Hi All,

I am currently in a dilemma. I have received my PR as a family of a BC (surinder Singh route) after an FTT appeal and a long wait. I am currently in a process of getting divorced and waiting for the decree NISI. Can I apply for citizenship now or do I have to wait for a year after PR? What documents can I provide to prove I am family of the BC as my marriage certificate is in the court but I am technically still spouse of a BC?

Also further to this I have achieved the PR in 2017 as per the FTT decision however the HO issued the card this month which certainly makes me think the PR was granted on the date it was issued and not actually when it was acquired. It will be great help if the experts here can help out as I dont want to lose the extortionate fees of Citizenship application if I make a wrong application.