Here we go, for stuff that is going in and out of the uk at least, could apply to a pass around knife for inspection and return I would think, (though would normally be used for a fix and return), package should be labelled as so..
"Temporary Admission Notice 200"
Here is all the small print from HMC.
http://customs.hmrc.gov.uk/channelsP...ent#P258_32591