Bomb disposal experts were called out after two suspicious packages were found at the Royal Mail sorting centre in Peterborough on Thursday, 1 May, addressed to the UK Independence Party (UKIP).
The alarm was sounded at about noon after staff at the sorting centre, in Papyrus Road, Werrington, became concerned about messages taped to two parcels.
Ordnance experts X-rayed the packages which were found to contain excrement. Senior staff then disposed of both parcels, which had been addressed to premises in Torquay, south Devon.
A Royal Mail spokeswoman said: “We can confirm that two suspect packages were found at the Royal Mail’s Mail Centre at Peterborough at lunchtime.
“The police and bomb disposal team attended and the all clear was given.
“The two items have now been disposed of. The building was not evacuated because the parcels were securely isolated and our collection and sorting operations which are carried out at the mail centre were not affected.”
A police spokesman said: “Explosives ordnance disposal experts attended as a precaution.”
He said messages taped to the parcels had given rise to concerns by staff.
The police spokesman said the packages were addressed to the political party UKIP, their headquarters are in Newton Abbot, in south Devon.