Royal Mail delivers letters, parcels, and other items as the UK's universal postal service provider.

The service aims to deliver mail to over 30million addresses in the UK, six days a week.

However, this isn’t always possible due to logistical issues linked to mail networks and “local issues” affecting delivery offices.

In its latest service update, Royal Mail apologised for the disruption that would affect postcodes in London, Manchester, Leicester, and Dudley, among other places.

The postal service said that letters and parcels may take longer to arrive than planned and that Royal Mail is “sorry for any inconvenience.”

According to Royal Mail, one mail centre reported that not all mail was processed and dispatched to schedule over the last 24 hours. “As a result, some mail may be delivered later than planned," it said.

Some mail posted from the London postcode areas of EC, N, W1 and WC, which are out for delivery today to other areas, could be affected.

In the past 24 hours, Royal Mail's air, rail, and road networks are operating as scheduled with no issues reported.

But that’s not the case for nine delivery offices across the UK. Royal Mail said: “We aim to deliver to all addresses we have mail for, six days a week.

"In a small number of local offices, this may be impossible due to local issues such as high levels of sick absence, resourcing, or other local factors."

On Wednesday, January 22, 29 postcodes were listed as “most impacted” by local issues.