My assumption is that anything unsolicited or that sounds like a bargain is a scam.

One recent one was an email saying the post office had tried unsuccessfully to make a delivery I needed to contact their "Ggnoffice to arrange to get a fresh delivery or collect the parcel.   Smelt funny, because the Post Office don't make deliveries any more since they split it from Royal Mail, and sold them both off to private companies, so I checked, and yes it’s a scam to collect information which could maybe give access to my bank account.