Originally Posted by Fran4USA

Make sure you read British Guys timeline link on the bottom of his post as it is an excellent help to give you an idea of the process and how long it takes.

Originally Posted by Tracym

The K-1 visa allows you to come to the US with the intent to marry. The minimum I've heard of to get that visa is 5 months - more likely 6-10. You could possibly visit the US during this time, but you would have to bring plenty of proof of ties to the UK to show your intent to return.

Once you get the visa, you must use it to enter the US within 6 months.

Once you enter the US, you must marry within 90 days.

If you enter through JFK you might still get a stamp which allows you to work immediately for the first 90 days. However... after you are married you still have to apply for the EAD (work permission). Depending upon how quickly you get married and submit the paperwork, and how quickly USCIS responds, you might have a gap in work authorization between the end of the 90 days and the arrival of the EAD.

If your concern is to be able to work immediately, you might want to do the other option Elvira mentioned - get married on a visit here (or in the UK) and apply for the CR1 spousal visa. Takes about the same amount of time, but you will be work authorized from day 1.