I am German permanently living in the UK since 2006, my wife is a non EU / non UK citizen. Our three children were born in the UK in 2011, 2014 and 2017. They hold German passports and I had always assumed them to be German citizens only.
We have all been granted settled status under the EU settlement scheme already. As I learned that Brexit introduces a deadline for being guaranteed dual German/British citizenship according to this information from the German foreign office I now want to apply for British citizenship for my children before the Brexit date.
Upon reading up on the citizenship requirements, I was surprised to learn that apparently my 2 children born in 2014 and 2017 do actually already unknowingly hold British citizenship as they were born after I had already lived in the UK for more than 5 years continuously. My questions are:
1.) Is it advisable that I should not apply for citizenship for my 2 younger children and instead simply apply for a UK passport for them to assert their British citizenship? This seems to be a lot cheaper. What kind of proof will I need to provide with these applications?
2.) Does the Brexit deadline quoted above for being allowed to hold dual citizenship still apply for these 2 children or can I do this at a later time and they will always have guaranteed dual citizenship?
3.) Am I understanding it right that this option is not available to my eldest child, that was born less than 5 years after I moved to the UK? For this child I should presumably apply for citizenship on the basis of its birth certificate and my settled status?