Ministers hope they will be able to negotiate and complete trade deals with other countries during any transitional period but they accept they won’t be able to implement them.
Speaking as the Brexit Secretary David Davis revealed future customs proposals with the EU, Government officials refused to be drawn on whether a third country trade deal could actually be signed.
It comes as Mr Davis told Sky News a temporary customs arrangement with the EU will be “in both sides’ interests” but any transition period should not exceed two years.
He said any interim customs union was there to avoid a “cliff-edge” for manufacturers after Brexit.
Mr Davis estimated the transition period would be roughly two years – with the deadline of the next General Election in 2022 as the “absolute maximum”.
The document sets out two broad approaches to a possible customs deal.
One aims to continue some existing arrangements the UK has with the EU, using technology to make custom requirements “as frictionless as possible”.
The second option is without precedent, which would involve the UK mirroring the EU’s requirements for imports where the final destination is the EU.
Video: Davis: We want ‘slick’ EU customs arrangements
The Government also says it has contingency plans in place to deal with the possibility of no agreement.
But there are increasing concerns that all the Government’s possible options mean businesses will be hit with extra red tape and increased costs.
For example, proposals for goods that do not comply with the EU’s trade policy would need a “tracking mechanism” where traders could claim “refunds” if tariff trades differ.
British Irish Chamber of Commerce responded saying it was cautious about the feasibility of some proposals being put forward in London on simplifying new trade barriers with Europe.
John McGrane, director of the association, said the ideas were a constructive contribution to the negotiations.
“The recognition of the need for an interim period to allow for the adoption of new systems and infrastructures will be welcomed by businesses who have long warned of the dangers of leaving the Customs Union without such a transition phase,” he said.
“It is important that this phase is as close to the status quo as possible with minimum disruption caused by tariff and non-tariff barriers.”
A European Commission spokesman said the UK position paper on customs would be examined carefully.
“We take note of the UK’s request for an implementing period and its preferences as regards the future relationship, but we will only address them once we have made sufficient progress on the termsof the orderly withdrawal,” the spokesman said.
“An agreement on a future relationship between the EU and the UK can only be finalised once the UK has become a third country.
“As (EU chief negotiator) Michel Barnier has said on several occasions, ‘frictionless trade’ is not possible outside the single market and customs union.”
To be in & out of the Customs Union & “invisible borders” is a fantasy. First need to secure citizens rights & a financial settlement
— Guy Verhofstadt (@GuyVerhofstadt) August 15, 2017
Guy Verhofstadt, the European parliament’s Brexit coordinator, tweeted ” To be in and out of the Customs Union and “invisible borders” is a fantasy.
“First need to secure citizens’ rights & a financial settlement.”
Labour’s shadow Brexit secretary, Sir Keir Starmer, branded the customs proposals “incoherent and inadequate” and “designed to gloss over deep and continuing divisions within the Cabinet”.