The UK government is seeking an interim trade relationship with the European Union in order to secure the "freest and most frictionless possible trade" with the EU after Britain exits the bloc.
London plans to ask Brussels to establish a "temporary customs union" after Brexit in March 2019, the UK Department for Exiting the EU said in a statement on Tuesday.
"During this interim period, which will be negotiated with Brussels, Britain will look to negotiate bold new trade relationships around the world," the statement said.
"One possible approach would be a temporary customs union between the UK and the EU," it said. "Our goal is to secure as frictionless trade as possible with the EU alongside the ability to forge trade deals around the world."
Britain’s membership in the EU customs union, which currently allows for the tariff-free movement of goods, will end along with its membership of the single market when it exits the bloc in March 2019.
The British government is preparing to publish its first detailed proposals on the future partnership with the EU.
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London is keen to start negotiating about its post-Brexit relationship with the EU, but Brussels has insisted that progress must be made on exit arrangements first.
Opening rounds of Brexit talks with the EU have made little progress, with European negotiators demanding greater clarity from the UK delegation.
The next round of talks is due at the end of August. Brexit talks formally began in June, a year after Britain's historic referendum vote to leave the 28-member European bloc.
Experts have warned it will be extremely difficult to negotiate a new UK-EU free trade agreement before Brexit, particularly as the EU has so far refused even to start trade discussions.
Opposition Labor lawmaker Chris Leslie, from the campaign group Open Britain, said the trade proposal represented "wishful thinking of the highest order."
"It is a fantasy to pretend we can have the freest and most frictionless trade possible with our largest partner when the government remains intent on pulling Britain out of the customs union," he said.