Royal Mail said tampering with letters was a criminal offence

The two employees now face being sacked after they were suspected of failing to deliver 12 tickets for the event.

The briefs were recovered and will now be delivered to the six residents in the city for whom they were intended by senior Royal Mail managers.

A spokesman said bosses acted quickly to deal with the allegations.

The man and woman were suspended from their posts at the Dundee East delivery office on suspicion of "tampering with and failing to deliver" the tickets ahead of the concert, on Saturday and Sunday at the city's Camperdown Park.

'Criminal offence'

A Royal Mail spokesman said a full investigation was currently under way.

"Delaying or tampering with mail is a criminal offence and Royal Mail can and will report the findings of its investigation directly to the procurator fiscal," he said.

"The security of the mail is of paramount importance to Royal Mail and we treat any such cases very seriously indeed."

The spokesman added: "Royal Mail will not allow the actions of two individuals to damage the reputation of the honest, dedicated postmen and women of Dundee who have been working hard to deliver these tickets and to help make this event a success for the city."