Please see below message from HMRC.
“We are aware that some customers have received telephone calls claiming to be from HMRC requesting personal information in order to receive a tax refund, or to demand money for an unpaid tax bill.
There is also another telephone scam where a recorded message is left, allegedly from HMRC, stating that HMRC are bringing a lawsuit against the individual and is going to sue them. The recipient is asked to phone 0161 8508494 and press “1” to speak to the officer dealing with the case. Please do not reply to the message.
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 this to Action Fraud, or you can call Action Fraud on 0300 123 2050 (Please note this number will be charged at your normal network rate). They are open Monday to Friday 09:00 – 18:00. Please also see HMRC security advice.”