Hi maheshangadi,
The default taxation method is the 'arising basis' on world-wide income, which means you would need to declare the annuity payouts in a Self Assessment Tax return.
If you are resident, but not domiciled in the UK, you may wish to consider the 'remittance basis' which is an alternative method of taxing income and capital gains.
Have a look at section 9 of:
Residence, domicile and the remittance basis: RDR1
To help you dedicde which is your best option.
Thank you.