“It still works by itself,” said Alex Veitch, general manager of public order for Logistics UK, a trading group.

The problem in the UK was exacerbated by a large shipment of medical masks, gowns, gloves and other equipment ordered for the National Health Service and temporarily stored in Felixstowe. At the end of November, the port operator announced that it was working with the government to free the mountain of shipping containers, some of which had been moved to former airfields. The port had also hired staff and extended its opening hours to remove the congestion.

Felixstowe had filed complaints prior to the pandemic. According to IHS Markit, it is one of the least efficient container ports in the world. It is struggling to cope with growing international trade and larger ships with more containers. Moving a container onto or from a ship in Felixstowe takes twice as long as some of China’s busiest ports, IHS Markit data shows.

With Felixstowe and other deep-sea ports mostly handling trade from Asia, these delays are not the same as in the New Year when the UK breaks away from its largest trading partner.

From January 1st, the UK’s trade relations with the European Union will change, introducing customs controls and possibly tariffs. While a trade deal is still being negotiated, the border processes will change regardless. For the first time, hundreds of thousands of businesses will have to meet customs controls and other new trade requirements.

The government has warned companies to prepare, but trade groups say some companies are too busy with the aftermath of the pandemic. Mr Ward said importers and exporters are less prepared, even though warehouses and transport companies have done what they can.

The crux of the matter is likely to be on the south coast, in Dover or Folkestone, the busiest places for goods to be transported between Great Britain and the European Union, either with trucks, which are transported by ferries across the English Channel, or with trains through the Channel Tunnel.