I've just found this statement for staff
Royal Mail
More heavy snow and freezing temperatures over the last few days are causing further significant disruption to mail services. This is affecting our ability to collect, process, transport and deliver the large, concentrated volumes of mail we receive at this, the busiest time of the year. Most delivery and collection services are still taking place today in the 3000 postcode districts across the country and we will continue to operate services in all areas, provided conditions are safe. Some delivery and collection services may be particularly disrupted in Northern Ireland, Wales, parts of Scotland and in parts of the South East, South West, North West, East Anglia and Thames Valley regions.
Whilst we have been and will continue to do all we can to get mail to customers, the current conditions, added to significant disruption throughout December, means there are unavoidable delays to mail travelling through our UK network. We have been operating national and local contingency plans for some time to keep moving and delivering mail.
We are continuing to make every effort to deliver to customers.