It is necessary to provide your mobile phone number when registering for State Savings Online as you will receive Verification Code SMS text messages to your mobile phone to help protect the security of your State Savings holdings. You will receive Verification Code SMS text messages to your mobile phone to: complete registration to verify your identity when you are signing in to confirm transactions on your holdings such as a repayment to your bank account or a password reset For more information see: What is two factor authentication (2FA)? What is a Verification Code?