LONDON — Pro-Brexit lawmakers pressed British Prime Minister Theresa May on Wednesday not to keep the U.K. tied to the European Union's customs union, amid warnings from the bloc that Britain must hurry up and decide what kind of future relationship it wants.
As May met with her divided "Brexit Cabinet" of senior ministers, 60 euroskeptic Conservative legislators argued that staying in a customs union with the EU would prevent Britain from striking new trade deals around the world.
Other lawmakers, and many businesses, want Britain to maintain customs alignment with the EU to avoid barriers with the U.K.'s biggest trading partner.
One option being considered by the British government is a "customs partnership" that would see the U.K. collect tariffs on the EU's behalf at ports and airports.
Prominent pro-Brexit Conservative legislator Jacob Rees-Mogg said the idea was "deeply unsatisfactory." He said a customs partnership "would not effectively take us out of the European Union; it would leave us de facto in both the customs union and in the single market."
Customs arrangements are key to solving the problem of maintaining an invisible border between the U.K.'s Northern Ireland and EU member Ireland. Both Britain and the bloc say there must be no customs posts or other infrastructure along the 310-mile (500-kilometer) frontier.
Britain rejects one suggestion from the EU — to keep Northern Ireland inside the bloc's customs union. The EU also says the U.K. has yet to propose a workable alternative.
U.K. Brexit Secretary David Davis said Tuesday there had been "push back" from the EU on Britain's suggestions so far, after EU Brexit negotiator Michel Barnier warned that Britain must come up with a proposal for the Irish border by June.
Britain and the EU want to strike an overall Brexit agreement by October, so EU parliaments have time to ratify it before Britain leaves the bloc on March 29, 2019.
But May's government is split between pro-Brexit ministers such as Foreign Secretary Boris Johnson, who want a clean break with the EU, and those including Treasury chief Philip Hammond who want to stay close to the bloc to protect the economy.
That has led May, who heads an unstable minority government, to put off taking a firm stand on key Brexit issues for as long as possible.
Cabinet Office Minister David Lidington said he expected the Cabinet to agree a position on customs and the border in "the next few weeks."