Royal Mail has published a list of postcodes where deliveries may not be guaranteed ahead of Christmas. The service has apologised to customers in 92 areas for the inconvenience and pledged to keep them updated.
A small number of local offices may be unable to deliver to some addresses because of issues including sickness absence, resources or other "local factors", according to Royal Mail. It said in such cases staff will rotate deliveries to minimise delays. In a statement, Royal Mail added: "We also provide targeted support to those offices to address their challenges and restore our service to the high standard our customers would normally receive."
The offices expected to see delays are:
Altens DO (AB10, AB11, AB12, AB35)
Belfast East DO (BT4, BT5, BT6, BT16)
Brixton DO (SW2)
Clevedon DO (BS21, BS49)
Dundee East DO (DD4, DD5, DD7)
Dursley DO (GL11, GL12, GL13)
Dyce DO (AB21)
Egremont DO (CA21, CA22, CA23, CA24, CA25, CA27)
Erskine DO (PA7, PA8)
Gloucester North DO (GL3, GL4)
Inverclyde DO (PA14-PA19)
Johnstone DO (PA5, PA6, PA9, PA10, PA12)
Lichfield DO (WS7, WS13, WS14)
Lisburn DO (BT26, BT27, BT28)
Londonderry DO (BT47, BT48)
Northwich DO (CW8 and CW9)
Nottingham South DO (NG2, NG12)
Paisley DO (PA1, PA2, PA3)
Pontefract DO (WF7, WF8, WF9, WF11)
Renfrew DO (PA4)
South Woodford DO (E18)
Sleaford DO (NG34)
St Helens DO (WA9, WA10, WA11)
Tipton DO (DY4)
Warrington DO (WA1, WA2, WA4, WA5, WA55)
Whitehaven DO (CA18, CA19, CA20, CA26, CA28)
Whitwood DO (WF6, WF10)
Wigan DO (WN1, WN2, WN3, WN4, WN5, WN6)
The latest lists falls on the final date for posting gifts and cards for those prepared to pay for Royal Mail's Special Delivery Guaranteed or DPD Gold.
Both guarantee a next day delivery or your money back, with the final date for Christmas being today, Tuesday, December 23.
The Post Office offers delivery options from carriers other than Royal Mail and Parcelforce Worldwide, with options including Evri and DPD in selected branches.
Postmasters had urged the public to send early to avoid being part of the 17% of those who have left it too late in previous years.
A survey for the Post Office found some 67% of Britons received Christmas cards and presents in the post after December 25.