This Guidance Note describes what to do if there is a bomb threat received via the post. The points to look out for are:
Grease marks on the wrapping or envelope
The package / envelope may have a smell of marzipan or machine oil
Wires or metal foil may be visible, especially if the package has been damaged in transit
A letter / package may feel overly heavy for its size
A letter / package may be heavier on one side or in the middle
A package may appear to be over-wrapped
A letter / package may be incorrectly addressed, show poor handwriting, spelling or typing
A letter / package may be over-stamped for its size or weight