When you start to work in UK, you will became a UK tax resident. You can be resident in more than one country at the same time.
It is possible to be resident in the UK and another country at the same time – ‘dual residence’. In this case you may need to find out whether there is a double taxation treaty between the two countries. These treaties are designed so that you generally don’t pay full tax twice on the same income or capital gains.
You can read all about on this link: Double taxation agreements – an introduction
and some more here: Meaning of ‘residence’ and how it affects your tax