The concept of residency does not exist in the same way in the UK as it does in Italy (residenza). The UK authorities define your residency mainly by the place where you file your tax return (i.e. your “tax residency”) and it is therefore perfectly possible to have residenza in Italy and file your tax return in the UK, provided you spend more than 183 days (i.e. half the year) in the UK.
Having a home in the UK also seems to be important if you wish to retain your tax residency there. Thanks to dual tax agreements between the UK and Italy, it is also perfectly possible to declare any profit or loss from a holiday home owned in Italy on a UK tax return. In fact there is a special section for doing so.
Your residence status elsewhere is irrelevant in determining your UK tax residence and it is possible to be resident for tax purposes in two countries. Residence is a complex area, so you will need to take advice for your specific circumstances. The HMRC provide this guide, which might be useful.