LONDON — It was something politicians spent an age debating, diplomats devoted years to negotiating and officials spent a fortune preparing for.
But on Thursday Britain made the embarrassing admission that it is still not fully ready for Prime Minister Boris Johnson’s biggest political project, Brexit.
Almost five years after Britons voted to leave the European Union, the government said it would wave through some goods arriving at British ports from the continent until January 2022 — a tacit admission that it lacks the capacity to perform the border checks required by Brexit.
The latest postponement to the Brexit process came as a relief to British businesses because it averts the risk of supermarkets running out of fresh produce, or car factories missing out on parts supplies.
But for the country that initiated the rupture with the 27-nation bloc, the delay suggests that the government underestimated, or underplayed, Brexit’s myriad complications.
“It’s probably the right thing to do but it points to some political failings because it was very predictable,” said Sam Lowe, senior research fellow at the Center for European Reform, a research institute based in London, referring to the government’s announcement Thursday. “Clearly the infrastructure isn’t in place to allow for full inspections in July.”
While Britain was a member of the European Union, British and continental firms could trade freely with minimal paperwork. But that all ended when Britain left the bloc’s customs union and single market on Jan. 1, and goods moving between the two sides now require customs declarations and, in the case of food products, health certification.
The British chose to phase in their checks gradually, but to have them in place in July. Now that deadline has been pushed back a further six months to January 2022.
By contrast, on Jan 1. of this year, Ireland and countries in continental Europe introduced their customs checks on goods arriving from Britain, a move that has hit some British exporters hard.
“There is already quite a lot of disruption with only 50 percent of the controls in place,” said Mr. Lowe, “I wonder if the government has looked at this and said, ‘We can do without having another problem like this right now.’”
Germany’s imports from Britain were down more than 56 percent in January compared with the same month in 2020, though some of this may be explained by stockpiling ahead of the Brexit trade changes and by the impact of the pandemic.
But almost three-quarters of Britain’s companies have faced delays moving goods in and out of the European Union in the last three months, according to a survey by Make UK, an organization representing manufacturers. Half said administrative and other costs associated with shipping had risen.
With tensions growing over trade, vaccine supplies and other issues, relations between London and Brussels have deteriorated into a state of semi-permanent friction.
In a statement, the British government said it was changing plans at the ports in response to complaints from businesses that had faced severe challenges during the pandemic.
“As a sovereign trading nation outside the E.U., we have freedom to take decisions in our national interest — and in the interest of our businesses,” said David Frost, who negotiated the Brexit trade deal with the European Union for Britain and is now a cabinet minister responsible for implementing it.
“We will now introduce border controls broadly six months later than planned to give traders time to focus on getting back on their feet as the economy opens up after a difficult year,” he said in a statement.
Still, the decision has prompted some mild ridicule from those who hark back to the 2016 campaign slogan urging voters to support Brexit and “take back control.”
The new ethos, critics joke, is to do this by not exercising any control at all.
British businesses welcomed the decision.
Ian Wright, chief executive of the Food and Drink Federation, a trade organization, said that without the delay, his sector faced “disruption, extra costs and potentially shortages of some goods, all of which were potentially avoidable.”
Applying the checks originally planned would also have had an impact on continental truckers’ willingness to come to Britain, which was “already fragile,” he said.
Many trucks delivering goods from continental Europe to Britain return empty to avoid time-consuming checks when they arrive in countries such as France, Belgium or the Netherlands.
Thursday’s decision followed the announcement of a separate and much more politically sensitive choice to delay fuller border checks on goods going from Britain to Northern Ireland.
Because trade with Northern Ireland is covered by a separate agreement with the European Union, Britain’s unilateral decision to delay checks on some goods headed there has angered the bloc, which says it violates international law.
The bloc’s executive body, the European Commission, is expected to begin legal action against Britain in the coming days.
Tensions between Britain and the European Union have alarmed businesses. Adam Marshall, director general of the British Chambers of Commerce, described Thursday’s decision as a welcome but temporary solution.
“What businesses want to see is an end to the damaging political rhetoric from both sides, and a focus on improving border flow for the long term,” he said.
Mr. Wright echoed that sentiment and said that Thursday’s announcement reflected not just a lack of infrastructure at British ports but also a worry that many continental firms were ill-prepared for the new paperwork.
But Mr. Lowe, the analyst, said that British preparations for Brexit had been hampered by political considerations and by the government’s desire to present the policy in a positive light. That meant that companies were given little information about the volume of red tape until late in the process.
“To prepare properly was to acknowledge that from an economic perspective Brexit was a bad idea and to acknowledge that it meant that businesses would face problems,” he said.