MPs have warned there is a significant risk that Border Force staff may be diverted from "crucial security functions" to deal with a post-Brexit increase in customs activity.
The Commons' Home Affairs Committee said the government's plans to boost border enforcement staff by 4% were “completely unconvincing” and called on the Home Office to "plan for a significant further increase in border staffing".
The government has pledged to place an extra 300 border staff by the time Britain quits the bloc, while HMRC has previously called for 5,000 extra staff to work on Brexit – prompting calls from the committee for "urgent co-ordinated staff planning" between the two.
"We find these plans for such a small increase in border staff completely unconvincing, particularly given the current uncertainty and the need for contingency planning," the committee said in a report published today.
"If new customs arrangements require a substantial increase in customs capacity which cannot be delivered in time, then there is a significant risk that Border Force staff will be diverted from crucial security functions, including preventing smuggling, the seizing of dangerous goods and immigration processes.
"The Home Office needs to plan for a significant further increase in border staffing and to ensure that arrangements are in place to prevent large numbers of staff being diverted away from other critical areas."
The report also said it is essential the government negotiates a transition deal, to give HMRC, Border Force and regulatory bodies time to "design, invest in and implement new systems".
In case the UK fails to negotiate a deal with the EU, ministers should set out early in the new year a timetable for when extra staff would be recruited and trained on a contigency basis, the committee said.
It accused the government of a lack of "focus, urgency and above all leadership" on Brexit planning. "Any progress seems to rely on working groups of government officials, with no
meaningful ministerial leadership," it said.
The report recommends a senior government minister be appointed to lead the delivery of post-Brexit customs arrangements, to coordinate the work of Treasury, the Home Office and
other departments, and to liase with the private sector.
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 outlined our proposals for ambitious future trade and customs relationships with the EU and are confident we will reach agreement.
"We will ensure we have the resources we need to continue to run effective customs, borders and immigration systems in the future.
“A good deal with the EU is in our mutual interest. We are optimistic about achieving that, but it is the duty of a responsible government to plan for a range of scenarios, which is exactly what we are doing."
The Home Office also said it will keep staffing under review as negotiations progress, and will ensure it has the resources and workforce necessary to run an effective customs and borders system.