Ok I see there is the warning about spam from HMRC But I had to laugh at one that came through to my junk box. Supposedly from Fedex and appearing in the preview window as "Fedex here Dear" Just have to laugh. Why do they even bother.
As for HMRC, having not that long ago signed up, maybe time to go back to good old fashion snail mail. Have yet to ever receive a spam letter that way.
Don't be put off by them just be careful. The latest one I received looked very convincing but the stated link was to a video games scrapping site. The previous one looked even more convincing especially as it quoted a reasonable refund due - in dollars.