The Polish Post Office informs that in connection with the decision on the suspension of air connections with the United Kingdom and road transport restrictions, coming into force on the night of 21/22.12, it suspends the acceptance of all postal deliveries to the United Kingdom. 
Also UPS Standard will not reach the UK quickly.

For the time being, the only way to ensure that your shipment will arrive in the UK is to choose UPS Saver.  UPS Saver is the only safe transport method for the time being.