Royal Mail managers have been accused of faking deliveries to secure their yearly bonuses by telling postal workers to falsely mark undelivered parcels as "inaccessible".
The practice risks parcels failing to arrive in time for Christmas across the country, with customers receiving "attempted deliveries" emails despite no one knocking at their door.
Postal workers have revealed they were instructed to record some parcel deliveries as inaccessible even when no delivery attempt was made.
The system allows customer operations managers to meet targets for parcels leaving Royal Mail depots, helping them secure their mid-year bonuses.
"That's a lie," the postal worker stated.
Justin Madders, the Minister for Postal Services, said he was "disturbed" by the reports and urged Royal Mail to investigate.
He called on Ofcom, the regulatory body, to examine the matter.
The Communication Workers Union said the findings were "further evidence of complete and deliberate mismanagement of the UK postal services".
A union spokesman said: "This is symptomatic of a managerial bonus structure that encourages dishonesty and cuts to service over treating employees properly, looking after customers, and growing Royal Mail."
Britons have been concerned about potential changes to Royal Mail delivery services in the near futureGETTY
The spokesman added: "It is important the public know that their postal workers have one hand tied behind their backs, and the current situation is no fault of theirs."
A Royal Mail spokesman also denied any network-wide delays, stating that over 99 per cent of items posted before last posting dates arrived before Christmas last year.
"There is no bonus incentive that would encourage items to not be delivered. This would be counter-intuitive to our business as a delivery company," the spokesman said.
The company explained that properties are only marked as inaccessible if they cannot access the building, if it is unsafe to deliver, or if adverse weather prevents delivery.
Customer operations managers can receive bonuses of up to £5,000 annually for meeting targets, while postmen and women receive just £200 in two £100 bonus payments.