Johnson is expected in the House of Commons to explain the eleventh-hour plan to U.K. lawmakers. It contains major changes to the proposed arrangements that would regulate trade between Ireland and Northern Ireland after Brexit.

The new proposals focus on maintaining an open border between the U.K.’s Northern Ireland and EU member Ireland—the key sticking point to a Brexit deal. The U.K. proposes to do that by keeping Northern Ireland closely aligned to EU rules for trade in goods, possibly for an extended period.

The plan has received a mixed response from European leaders and seems to fall far short of meeting their requirements for keeping an open border.

The European Parliament’s chief Brexit official, Guy Verhofstadt, said the plan doesn’t give Ireland sufficient guarantees.

“The first assessment of nearly every member in the Brexit Steering Group was not positive,” he said, adding that the group would flesh out objections Thursday.

Johnson has presented the proposal as a compromise. It would create “an all-island regulatory zone on the island of Ireland, covering all goods including agrifood.” That would keep Northern Ireland in a regulatory zone with the EU for food, agricultural and industrial products, removing the need for checks.

The U.K. proposal doesn’t put a time limit on that status, though it would have to be renewed every four years by the Northern Ireland Assembly. However, that assembly has been suspended for more than two years by a dispute between the main Unionist and Nationalist power-sharing parties.

Under the plan, there would still need to be customs checks, but Johnson suggested they could be carried out away from the border at “other points on the supply chain.”

Johnson insists Britain will leave the European Union on Oct. 31 with or without a deal, but Parliament has passed a law requiring him to seek an extension if no deal is reached.

Johnson’s position is tenuous because he doesn’t have a working majority in Parliament.