Auditors have warned that delays and disruption may occur at border entry points like the Port of Dover if the government fails to take steps to prepare for the UK’s departure from the EU.

A report by the National Auditor Office says border controls will need to change to take account of the UK’s Brexit and expresses concern that arrangements may not be ready by 2019.

It says the Port of Dover could see delays after Brexit because of the need to make many more customs checks. It also predicts bottlenecks and congestion are possible as the time needed to make checks will increase.

Auditors estimated that immigration officials would need to make 230% more decisions a year if the existing regime for travellers from outside the European Economic Area (EEA) is extended to European arrivals.

If customs declarations were needed for trade between the UK and EU, the total number could soar by 360%.

The report warns that the Port does not have capacity for inspecting and checking vehicles and it would be wrong to think that border controls can continue by “doing more of the same.”

It says: “This assumption may not prove true and in some circumstances, the ability to scale up operations will be constrained by physical and other infrastructure.For example, there are a limited number of inspection bays available to search incoming traffic at the Dover port, and there are physical constraints on creating new inspection bays.”

“Port entries that are described as ‘roll-on roll-off’ services, where increased border controls could limit the flow of goods and people, creating bottlenecks and substantially increased waiting times. If these persisted then perishable goods could be damaged and supply chains could be interrupted.

“New border management activities may need to be designed and implemented in a compressed time frame and with potentially limited lead times, posing challenges for the cost-effective delivery of those activities.”

“Port entries that are described as ‘roll-on roll-off’ services, where increased border controls could limit the flow of goods and people, creating bottlenecks and substantially increased waiting times" - NAO report

MP Meg Hillier, who chairs the all-party public accounts select committee, said: "How the UK manages its borders has been a question of significant concern in the Government's approach to Brexit. But this report from the NAO underlines the sheer scale of the task ahead.”

"Add to that the Home Office's poor track record with projects like e-borders and for all the Government bluster about Brexit it's difficult to see how, practically, it will be able to deliver any of these huge changes in time."

A Government spokesperson said: “We are fully focused on making the UK’s exit from the EU, and our new trading relationship with the world, a success.

“We have set out proposals for an ambitious future trade and customs relationship with the EU and we will be setting out proposals for the future immigration system in due course.

“We will of course ensure we have the resources we need to continue to run an effective customs, borders and immigration system in the future."