This scam is becoming widely reported and seems to be randomly targeted at everyone. You will receive a spoofed call, allegedly from HMRC, stating you have an outstanding tax bill to pay. The recipient is asked to share an email address where they share their Bitcoin QR code and then instruct you to visit an ATM location and insert your cash. They also mention they will come to visit you to collect the receipt the following day.
GENUINE ORGANISATIONS LIKE HMRC WILL NEVER CALL YOU AND PRESSURE YOU INTO INSERTING CASH INTO ATM & BUYING BITCOIN!
HMRC takes security very seriously but you need to be alert. If you cannot verify the identity of the person making the call you should not disclose your personal details. You should report these incidents on the Action Fraud website, or you can call them on 0300 123 2040 (Please note this number will be charged at your normal network rate). They are open Monday to Friday 09:00 - 18:00.
To learn more about dealing with phishing and scams visit GOV.UK