1st class gold Security Machin forgery.
One of several types which have been produced.
The security codes suggest a counter sheet stamp - coded MAIL MAIL. The iridescent text is very clear. The 'phosphor' bands of course are not phosphor. All these are on paper, some with postmarks some uncancelled. In most cases the paper is cut clear of the stamp.
Seven examples of this type available - please choose from selection box.