There is no such thing as an English accent. There are dozens of them! The result is that English ears will pick up on quite tiny differences and to totally eradicate any trace of being Danish will take years.
My best friend is German and after over half his life here - he's 50 now - he still sounds obviously German to me, but then he just isn't trying to change it and why should he? His accent has definitely moderated over the years just from being here, and he sounds more English than German politicians speaking English, but really, who cares? He's German and proud of it, and quite right too.
The obvious name that comes to mind when I think of Denmark is Sandi Toksvig, well known on British TV. But she is the daughter of a Danish foreign correspondent and went to school in England when he was posted there, so she has no trace of a Danish accent at all. That's the thing - your accent tends to get settled as a child and it's hard to change later on.
An elocution teacher will help but getting to the point where any English person mistakes you for English is VERY unlikely.
As Clive said, there are hundreds of regional accents in England and the rest of UK. I assume you want one as shown by Hollywood.
It's very hard to change your accent completely after your late teens. However, you would pick up some of it. I had a Canadian relative that lived in UK for over 60 years. He still sounded Canadian.
Unless you are an EU citizen you need a Student Visa or a Work visa to live in England
So many accents in England & REST OF UK..Not all like the queen...
You will pick up an accent automatically and unconciously. I once worked abroad and came home with a West Indian accent.
i came home with an accent. don't worry about it.
