Hi Sachin Grover,
Yes, when you have been resident in the UK for at least 15 of the 20 tax years immediately before the relevant tax year, you are considered 'deemed domiciled'
Deemed Domicile rules
This means that the remittance basis can no longer apply and that your world-wide income must be taxed under the arising basis, whether or not the income or gains is remitted to the UK.
The income you mention is taxable and should be declared in a Self Assessment tax return.
Thank you.