Scammers are making automated calls purporting to be HMRC, claiming you owe tax and need to pay immediately.
Whether you pay income tax or National Insurance, the effect on your cash flow is the same. The payments are a necessary part of our obligation to fund the activities of State, but the self-employed are often surprised that their bi-annual tax payments cover both “taxes” - NIC and income tax.
It would seem that HMRC is keen to plug the apparent drain from VAT receipts when contractors and sub-contractors charge their customers VAT and then go missing, keeping the VAT for themselves. This is described in legislation as “missing trader fraud”.