An audit from the British government's National Audit Office (NAO) estimates that post-Brexit border controls will cost the country at least £4.7 billion ($5.9 billion) in programs to manage the flow of imports from the European Union. 

According to the Guardian, that figure would cover the cost of 13 border-related programs to deal with physical checks on plant and animal imports, safety and security declarations, and various other costs for ports receiving goods. The initial phase of post-Brexit border controls requiring health certifications for EU meat, dairy and plant imports began on January 31, 2024. Physical checks came into force on April 30. 

Read More: New Brexit Rules Could Add Billions to Cost of Meat, Dairy Imports into U.K.

Border controls on EU imports were delayed by the British government five times since the Brexit transition period ended on December 31, 2020. The NAO says that those delays — and the ensuing difficulties it caused for businesses trying to prepare for the changes — were at least partially to blame for its £4.7 billion estimated price tag. 

"The repeated delays in introducing import controls, and difficulties forecasting requirements, have resulted in government expenditure on infrastructure and staff that were ultimately not needed," the NAO said in its audit.

Although the U.K. has set a goal to have the "world's most effective border" by 2025, the NAO further criticized that plan as lacking "a clear timetable" or a concrete delivery plan for collaborating government agencies.