Hi, there is no attachment in your message.
As already mentioned, these are fake communications intended to extort money from you. Once you start responding to their email communications, they will collect your contact number and call you, pretending to be from the UK, asking for some money under the guise of a deposit. After you make the payment, they will not respond further. If you are still very curious about this employment opportunity, contact the employer (refer online for the contact number and do not trust the number provided in the email) to verify.
Alternatively, you can email the British Deputy High Commission in Chennai to verify.