How can I determine the marital status, and any previous marriages, of a UK citizen living in the UK?
You can get a record of the family tree from General Register Office, through family tree you would be able to get much info about a person.
GRO has all the records registered in England and Wales from July 1837. You’ll need to look at parish records to trace back further.
You can put a request online and pay a fee they can also provide you a copy of marriage certificate in-case if you know both husband and wife name.
Depending on when you think the couple married, you can search online at FreeBMD.co.uk with only one partners's name. Regional searches, if you know where the event would have taken place, are quicker, but logically the more detail you know, the easier it is to check.
There is no charge for this service.
The result will show the second partner's surname, so you can do a 'reverse search' using that to display their given names.
As the name implies, Births, Marriages and Deaths are all searchable.
I have often found that the christian name I know a person by is actually their second or third name, or a 'shortened' version, so look for them by a single letter and remember that alternative spellings of common names are quite frequent.
Unfortunately, the records currently available only run to 1992, so unless you want to volunteer as a transcriber ( with access to everything ) you will have to use alternative methods.
Good luck with your searches.
As usual, it depends.
You can get a copy of a marriage certificate from https://www.gov.uk/order-copy-birth-death-marriage-certificate if you know the names of both partners. Apparently anybody can get this, as long as they know the names. Not that this will help you, since you need the partner's name and you don't have that (except if you knew that John Smith was engaged to Jane Jones, you could ask for a copy of their marriage certificate). So we have clear evidence that the UK government knows exactly who is married. There are two problems with this: People can change their names, and if you want to check if John Smith is married, you are out of luck. There are probably thousands of them.
If you get married in the UK, the government website says that if you were married, you need to bring a divorce certificate or death certificate of your partner in order to get married. The site does not say whether and how they know that you are married. I assume they will be able to regularly check that you have already married. Obviously getting married twice is bigamy and a rather serious crime.
Is there a way to ask the UK government if a person is married? Probably not if you are any random person. Possibly yes if you are working at a registry office in a country that has good relations with the UK.