Refugees don't get citizenship anywhere. Illegals born in US get citizenship but not anywhere else including UK.
If you were born in the UK on or after 1 January 1983, you’ll be a British citizen if your mother or father was either:
- a British citizen when you were born
- ‘settled’ in the UK when you were born
‘Settled’ means you can stay in the UK without any time restrictions. This includes people who have one of the following:
In most cases you’ll be a British citizen if your mother or father was born in the UK or naturalised there at the time of your birth.
https://www.gov.uk/types-of-british-nationality/british-citizenship
Germany
Children of parents with foreign passports receive German citizenship at birth if one parent has lived in Germany for at least eight years and has unlimited residency status. The children also get to keep their parents’ citizenship. At age 21, they are supposed to choose one of the two nationalities. However, the obligation to give away one passport has in recent years been watered down by new regulations and there are a lot of exceptions to the rule meaning more and more children of foreign parents continue to keep their dual citizenships after their 21st birthday.
United Kingdom
A child born in the United Kingdom is automatically a British citizen only if one parent is a citizen of, or settled in, the U.K.
A U.K.-born child without a parent who fits the bill can become a British citizen later — either if they live in Britain till they are 10; or if either parent becomes legally settled in Britain.
Italy
Those born in Italy can ask, when they turn 18, to become an Italian citizen if they have continued to live in Italy since birth. The request must be formally made before the 19th birthday. It’s usually a straightforward process for these young people.
France
All children born in France of foreign parents automatically gain French citizenship at the age of 18, if they live in France and have lived here for five years since the age of 11.
Greece
In Greece there is no birthright citizenship. So if a child of foreign parents is born here, it doesn’t give them the right to Greek citizenship.
Czech Republic
Birthright citizenship is only given to foreign children born in the Czech Republic if the parents are considered stateless or if one of the parents has a residency permit for a period longer than 90 days.
Spain
Citizenship is automatically granted to children born in Spain who have at least one Spanish parent. If neither parent is a Spanish citizen, children born in Spain to legal residents can obtain citizenship after one year.
https://www.pbs.org/newshour/world/birthright-citizenship-regulations-europe
