Birthright citizenship means being a citizen at the moment of birth. So, no, the UK doesn't have it from what you have written.
Well, yes it does often, and depends on circumstance. The guidance changes over time. It also depends on when you were born and EU free movement before Brexit. If you were born before 1 January 1983, you are a British citizen automatically at birth, unless your parents were diplomats or enemy aliens.
https://www.gov.uk/check-british-citizenship/born-in-the-uk-or-a-british-colony-before-1-january-1983
What's interesting is if you read further is that if you’re not recognised as a citizen of any country, you may be able to register as a British citizen depending on when and where you were born.
There is a provision for stateless individuals then. If the US gets rid of birth citizenship, what happens to stateless individuals.
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Born in the UK or a British colony before 1 January 1983
You’re usually a British citizen automatically if you were born in the UK.
There are 3 exceptions. You will not be a British citizen if:
- your father was a diplomat working for a foreign country
- your mother was a diplomat working for a foreign country and you were born on or after 10 April 1968
- your father was an ‘enemy alien in occupation’ in the Channel Islands during World War 2
Born in the UK between 1 January 1983 and 1 October 2000
Whether you’re a British citizen depends on where your parents were from and their circumstances. There are different rules if, when you were born:
at least one of your parents was a British or Irish citizen
at least one of your parents was a citizen of an EU or EEA country
neither of your parents was a British, Irish, EU or EEA citizen
You’re automatically a British citizen if you were adopted by a British citizen in a UK court.
If at least one of your parents was a British or Irish citizen when you were born
You’ll be a British citizen if when you were born at least one of your parents was either:
a British citizen
an Irish citizen living in the UK
If the parent that meets these conditions is your father, he must have been married to your mother when you were born.
If at least one of your parents was a citizen of an EU or EEA country when you were born
You’re automatically a British citizen if when you were born at least one of your parents was both:
a citizen of a country that was in the EU or the EEA at the time
living in the UK with free movement rights
If the parent that meets these conditions is your father, he must have been married to your mother when you were born.
Countries that were in the EU or EEA between 1 January 1983 and 1 October 2000 (other than the UK and Ireland)
Belgium, Denmark, France, Germany, Italy, Luxembourg and The Netherlands were in the EU by 1 January 1983.
Greece was in the EU by 1983 but Greek citizens did not get full free movement rights until 1 January 1988.
Although Portugal and Spain became EU members on 1 January 1986, their citizens did not get full free movement rights until 1 January 1992.
Austria, Finland, Iceland, Norway, and Sweden joined the EEA on 1 January 1994.
Liechtenstein joined the EEA on 1 May 1995.
If your parents were not British, Irish, EU or EEA citizens when you were born
You’re only automatically a British citizen if when you were born at least one of your parents lived in the UK and had one of the following immigration statuses:
indefinite leave to remain (ILR)
right of abode
right of re-admission
If the parent that meets these conditions is your father, he must have been married to your mother when you were born.