Cabinet sources say draft of plan has prompted a fresh row as it does not include end date

Theresa May is facing a backlash from the Brexit secretary, David Davis, over the government’s backstop plan to avoid a hard border in Ireland.

Cabinet sources confirmed a BBC report that a four-page draft of the backstop proposal circulated to ministers has prompted a fresh row, because it does not include a legally enforceable end date.

Davis in particular was keen to see a firm end date be put in place for the plan, which would keep the whole of the UK in key areas of the customs union until a permanent solution to the Irish border problem can be found.

Davis helped to clinch agreement on the backstop in the cabinet Brexit subcommittee last month, in the face of objections from other leavers including Boris Johnson and Michael Gove.

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Johnson subsequently warned that the prime minister should ensure she delivered a Brexit deal that avoided the backstop having to be used. “Brexiters fearing betrayal over the customs backstop must understand that the PM has been very clear that it is not an outcome we desire; we want a deal with the EU and she will deliver it,” he said.

Downing Street played down the row on Wednesday, saying the backstop was only ever intended to be temporary. “It’s important that it’s time-limited even outside of the fact that we don’t expect or want it to happen,” a source said.

Pressed on whether the last meeting of the Brexit subcommittee had signed up to the details of the backstop plan, the source said, “they agreed the policy of what it would look like – and of course that there needs to be one”.

The subcommittee is due to meet again on Thursday, with a related simmering dispute about Britain’s future customs arrangements still unresolved.

When news of the backstop plan emerged last month, it infuriated hardline Conservative backbenchers who fear that it could become the post-Brexit norm.

Jacob Rees-Mogg, who chairs the pro-Brexit European Research Group of Tory backbenchers, went so far as to question whether the government remained committed to delivering Brexit.

The latest clash between the prime minister and her Brexit secretary comes after the pair also disagreed about the timing of publication for a white paper on the government’s Brexit stance.

Davis was keen to produce a detailed document before the European council at the end of June but the prime minister is more cautious.

May refused to give an answer when asked by Jeremy Corbyn at prime minister’s questions when it would be published.

Rumours were circulating in Westminster on Wednesday that Davis had threatened to resign over the details of the backstop plan.

Britain signed up to the idea of a backstop in the deal reached with the EU27 in December but May rejected a draft subsequently presented by Brussels that would in effect keep Northern Ireland in the single market.

Any plan that involves a special status for Northern Ireland is anathema to May’s allies in the Democratic Unionist party, who reject the idea of any differential in treatment between the region and the rest of the UK.

The EU27 has been waiting for the government to publish its alternative draft backstop proposal, which is expected to include the whole of the UK temporarily applying the EU’s external tariff – a plan that would limit the ability of the trade secretary, Liam Fox, to strike new deals with non-EU countries.