Thanks for your question
Yes if its more than your personal allowance (as you are still awarded UK personal allowances as a British citizen - which is £9440 a year)
However as you are not UK resident, then unless you have registered for the Non Residents landlord scheme, then either your tenants (or managing agent if you have one) should be paying the tax over to HMRC (and then you complete self assessment returns each year and declare rents, less expenses and tax suffered)
If you are registered (or get registered) for the non resident landlord scheme, then you still complete a self assessment tax return each year but just pay any tax due annually.
I have added a link for the Non Resident landlord scheme
Do feel free to ask any follow up questions