Moray MP Douglas Ross has urged Theresa May to make clear when the Commons will have its say on her Brexit deal.
He told the House earlier that he had come to the conclusion he could not support the withdrawal deal and political declaration on a future relationship.
And he insisted members should be allowed the opportunity to explain their views.
Intervening on the prime minister’s statement, the Tory backbencher said: “I am one of the hundreds of members who was hoping to participate in the debate this evening and tomorrow.
“I would like the opportunity to explain to the people of Moray why I came to the conclusion that I could not support the prime minister on her deal.
“But may I ask the prime minister a question that has so far been evaded across the House?
“Not only the members in this chamber but our constituents deserve to know when the vote will finally be taken. When will it be?”
Mrs May said until discussions had begun with the EU, it would not be possible to say the “length of time that will be necessary for them”.
She added: “I want to work as quickly and as urgently as possible.
“We need to enter those discussions with the European Union, and until we have done that, it is not possible to give a date.”