Recorded message advising that I had a tax debt and could be put in prison. I was to hit "1" on the phone to continue. I didn't have time to continue and hung up. I later rang the number and it was a legal firm who knew nothing about it. The scammer was able to not only block their number but have a fake number replace theirs. It was clearly a scam but I checked my tax record in My Gov anyway and everything is fine.