With most of the shops in the UK still unable to trade, people have been having to make a lot of their purchases online. This may be from supermarkets, if they do not want to leave the house or are self isolating, or clothing / homeware stores. This may be a new way of shopping for many people who do not normally shop online.
Although many of the retailers are now getting to grips with the large number of orders they have seen, it has taken a while for them to catch up with some deliveries. Often delivery times are taking longer than they usually would and there does seem to have been a number of errors that have occurred with parcels ending up at wrong depots etc.
Many of the shops are set to reopen later on this month and that should elevate some of the pressure on the delivery companies.
It may be that more people decide that they no longer want to shop in person at the store and continue to order online even after all this has finished. This will ease congestion on the high streets but may make it harder for some of the smaller retailers who maybe do not trade online to survive.