LONDON (AP) — The British government says there could be lines of 7,000 trucks at the English Channel and two-day waits to get into France immediately after the U.K. makes its economic break from the European Union at the end of the year.

Michael Gove, the minister in charge of Brexit preparations, described that as a worst-case scenario in a letter to logistics firms. He is set to give more details to Parliament on Wednesday.

The government letter says that between 30% and 50% of trucks wanting to cross the Channel may not be ready for new paperwork and regulations that will come into effect on Jan. 1.

"This could lead to maximum queues of 7,000 port-bound trucks in Kent and associated maximum delays of up to two days," the document said.

The delays could last at least three months until companies get used to the new systems and requirements, Gove's letter states.

Haulage and logistics companies accused the government of being woefully unprepared for the changes coming in just over three months. The government's Smart Freight system, designed to reduce the risk of cargo delays, will still be in a testing phase in January. Work to recruit and train 50,000 new customs workers is nowhere near being finished.

"We've been consistently warning the government that there will be delays at ports, but they're just not engaging with industry on coming up with solutions," Road Haulage Association chief executive Richard Burnett said.

The U.K. withdrew from the EU's political institutions on Jan. 31 but remains in a tariff-free transition period until the end of the year while negotiators try to work out a future trade relationship.

Even with a deal, Britain will be leaving the bloc's single market and customs union, meaning some new checks and trade barriers. Without a deal there will be much greater disruption, with the U.K. and the EU having to slap tariffs on each others' goods.

A report by political research group U.K. in a Changing Europe estimated that, in the long run, the economic hit from a no-deal Brexit could be three times the impact of the coronavirus pandemic. The British economy contracted by a fifth between March and May as the country went into lockdown, though it has since recovered some of that ground.

The EU and the U.K. say a deal must be struck by October so it can be approved and ratified before Jan. 1. But negotiators remain at loggerheads on key issues, especially European fishing boats' access to U.K. waters and competition rules for businesses.

Chief EU negotiator Michel Barnier is due to hold talks with his British counterpart, David Frost, in London Wednesday ahead of a ninth formal round of negotiations next week.

The climate for the talks has been further chilled by British Prime Minister Boris Johnson's introduction of a bill that would give the U.K. the right to override parts of the legally binding withdrawal agreement it struck with the bloc less than a year ago.

The bill has infuriated the EU, which has threatened legal action if Britain does not reverse course by the end of September. Johnson shows no signs of dropping the bill, which is currently making its way through Parliament.

The legislation has also caused an uproar in Britain. Five former prime ministers criticized Johnson's willingness to break international law, and the government's top legal civil servant and most senior law officer for Scotland have both resigned.