Andrea Leadsom has told MPs their only real Brexit choice is whether to accept any final deal Theresa May negotiates with Brussels when it comes to the Commons to be signed off.

Leadsom, the leader of the house, sought to narrow the options for MPs on Thursday, saying that “the reality before the United Kingdom” would amount to an either/or choice on May’s deal, even if the Commons were to debate possible amendments.

The cabinet minister addressed MPs the day after the Brexit secretary, Dominic Raab, provoked backbench outrage by saying parliamentary approval for May’s deal needed to be unconditional because amending it could prevent it from being ratified.

Some MPs are considering an amendment to the approval motion to authorise a second referendum. Other amendments could extend or reduce the transition period during which the UK stays in the single market after Brexit.

Valerie Vaz, the shadow leader of the house, accused the government of trying to “take sovereignty away from parliament” and said that Raab’s warning about amendments meant there would not be a meaningful vote on a final deal. “This is the most outrageous power grab,” she said.

Leadsom acknowledged that it would ultimately be for the Commons to decide how it handled the “meaningful final vote” to approve the Brexit deal, because it would be organised by a business motion that MPs would vote on. Her remarks, however, were a clear sign that the government wants to reduce the choice availableto MPs.

“What I want to say is that the house will be aware that whether or not debate should be organised through a business of the house motion, and the form of any such motion, will be in the hands of the house itself, which has the power to amend, approve or reject such a motion,” Leadsom said.

“But it is very important to recognise the question that will be in reality be before the United Kingdom, and that is whether or not to accept the deal that the government has negotiated with the European Union.”

It emerged on Wednesday that Raab had written the Commons’procedure committee hoping to secure its endorsement of his position that “amendments … may actually result in the government being unable to ratify the withdrawal agreement through creating uncertainty as to whether such approval had in fact been given”.

A revolt led by the Labour MP Helen Goodman at the committee’s meeting prevented MPs from endorsing the minister’s conclusion. The committee is now seeking further opinions from independent constitutional experts over the next week before issuing its guidelines on how the debate should be organised.

Pro-remain Tories have also expressed concern. Nicky Morgan said on Twitter: “This appears to be an attempt by the executive to frustrate our sovereign parliament – it is clumsy, it won’t succeed and it shows how hollow ‘taking back control’ was for some people.”

Tory strategists, worried about whether hard Brexiters will vote for May’s deal, are hoping to win the support of Labour MPs in leave-supporting seats, arguing that it is in the national interest to vote for Brexit. Their argument is that MPs will be left with only two choices once the negotiations conclude: an imperfect deal negotiated by May or a highly damaging no deal.