Royal Mail operates an air, rail and road network to keep post and parcels moving between distribution hubs and processing centres across the UK.

Christmas is Royal Mail's busiest period, with around double the volume of letters and parcels processed. But the aftermath of Storm Darragh is causing delays in parts of England and Wales today.

The postal service assured customers that delivery and collection services will occur across the UK today. However, there is some disruption due to the air network and mail centres not running to schedule.

A Royal Mail statement read: "Our air network services operated to schedule over the past 24 hours, with the following exception: Last night, technical issues cancelled a flight from East Midlands airport to Belfast airport."

The service suggested that some mail posted yesterday in the Midlands, southwest and north of England, Wales and central and southern Scotland, due for delivery today in Northern Ireland, "may arrive later than planned".

As for the postcodes most impacted by network disruption, Wales and southwest England fared the worst.

Two mail centres reported that not all mail was processed or dispatched to schedule in the past 24 hours, potentially leaving three postcodes in the lurch today.

Exeter

Royal Mail warned that some mail posted yesterday in the EX and TQ postcode areas may be delayed if it is due for delivery today in other parts of the UK.

Swansea

Mail posted yesterday in other parts of the UK that is due for delivery today in the SA postcode area could arrive later than planned.

Royal Mail says it aims to deliver to all addresses it has mail for, six days a week. However, they acknowledge that this may temporarily not be possible in a small number of local offices due to local issues such as high sick absence levels, resourcing, or other local factors.

In those cases, deliveries are rotated to minimise the delay to individual customers. The service said: "We also provide targeted support to those offices to address their challenges and restore our service to the high standard our customers normally receive."

Dozens of local delivery offices are currently impacted by local factors, including: 

• Abercarn DO (NP11)
• Abingdon DO (OX13 and OX14)
• Basingstoke DO (RG21-RG26 and RG28)
• Bethnal Green DO (E2, E8 and E9)
• Bordon DO (GU35)
• Bow DO (E3)
• Burnham On Sea DO (TA8 and TA9)
• Canterbury DO (CT1 - CT6)
• Carterton DO (OX18)
• Clevedon DO (BS21 and BS49)
• Coalville DO (LE67)
• Dunstable DO (LU5 and LU6)
• Fareham DO (PO14 - PO17)
• Finchley Church End DO (N3)
• Folkestone DO (CT18, CT19 and CT20)
• Frome DO (BA11)
• Gosport DO (PO12 and PO13)
• Havant DO (PO9 and PO10)
• Keith DO (AB55)
• Kendal DO (LA8 and LA9)
• Kingswood DO (BS15 and BS30)
• Lanark DO (ML8 and ML11)
• Leicester East DO (LE2, LE5 and LE7)
• Margate DO (CT7 - CT9)
• Ongar DO (CM5)
• Oxford East DO (OX3, OX4, OX33, OX44 and OX49)
• Plymouth North DO (PL2 and PL3)
• Plympton DO (PL7)
• Portsmouth DO (PO1 – PO6)
• Radstock DO (BA3)
• Reading East DO (RG4 - RG6 and RG10)
• Swan House DO (LE1, LE3, LE7, LE8, LE9, LE19 and LE95)
• Thatcham DO (RG18 and RG19)
• Tonbridge DO (TN1-TN5 and TN9-TN12)
• Wallingford DO (OX10 and OX49)
• Wantage DO (OX12)
• Waterlooville DO (PO7 and PO8)
• Weston-super-Mare DO (BS22, BS23 and BS24)
• Whetstone DO (N20)
• Woodbridge DO (IP12 and IP13)