Royal Mail has vehemently denied claims that more than two million parcels and letters have been lost or delayed in the Christmas post.
A report in The Sunday Times said that customers across the UK were facing Christmas without presents as Royal Mail allegedly struggled to cope with the boom in online buying.
But Royal Mail has said it is fully on course to deliver the nation's festive mail on time.
The organisation's head of media, David Simpson, said: "These claims have no credibility at all. Royal Mail is on track to deliver, by Christmas, all the mail that was posted before the final post deadline given. We have already delivered the vast bulk of the mail, and the last cards and packages will be delivered on Monday. We are on track. A lot of online buys are delivered by other companies and we can't speak for them.
"We put on extra flights and trains for the Christmas delivery period. We plan 12 months ahead and employ 20,000 extra people."
The Sunday Times quoted angry customers as saying delivery workers were posting "you were out" cards when they were in fact at home.
The newspaper also claimed that undelivered parcels were languishing in depots, where people had to queue for up to two hours to collect their post. But Mr Simpson said he was not aware of any depots with significant queuing problems. He added: "It wouldn't make sense for a postman not to deliver something when he could. If there are isolated cases then we would look into it."Reuse content