The Latest on Brexit (all times local):

9:40 a.m.

Prime Minister Boris Johnson's plan to get Parliament to approve his Brexit deal with the European Union has been thrown into doubt.

Lawmakers will first vote on whether to withhold approval until legislation to implement the agreement has been passed. That would bring another law into play that would force Johnson to seek a Brexit delay from the European Union.

House of Commons Speaker John Bercow said would allow a vote on an amendment that essentially puts the vote on the deal off until another day.

Those behind the amendment say it will remove the risk that the U.K. could stumble out of the bloc without a deal on Oct. 31 because the law is not in place.

The vote is due later Saturday.

8:40 a.m.

Prime Minister Boris Johnson's Brexit plan faces what is expected to be an extremely tight vote as Britain's Parliament prepares for its first Saturday session since the 1982 Falklands war.

At stake is a new divorce plan agreed between the British government and the other 27 European Union nations at a summit Thursday.

Johnson hopes for success in getting a fractious Parliament to back the deal after his predecessor, Theresa May, failed three times to get lawmakers behind her plan.

Johnson does not have a parliamentary majority but he is hoping to woo some opposition Labour Party lawmakers to his side.

He said in The Sun newspaper on Saturday that a vote for the plan would bring a "painful chapter in our history" to an end.