There had been speculation that the deal could be voted on early this week, but updating MPs after securing a delay to Brexit at a last week’s EU summit, the Prime Minister said there was “still not sufficient support in the House” to ensure victory.
MPs are now expected to seize control of the Commons order paper tonight and force the government to hold ‘indicative votes’ on their preferred alternative Brexit plans.
The government could still bring its deal before the Commons later this week, after indicative votes are expected to be held on Wednesday.
“But it is with great regret that I have had to conclude that as things stand, there is still not sufficient support in the House to bring back the deal for a third Meaningful Vote.
“I continue to have discussions with colleagues across the House to build support, so that we can bring the vote forward this week, and guarantee Brexit.”
The Prime Minister said the government would oppose an amendment put forward by the Tory MP Oliver Letwin, requiring indicative votes to be held, and warned that the government would not be bound by the results if they went against manifesto commitments to leave the EU customs union and single market.
She said they were an “unwelcome precedent to set, which would overturn the balance of our democratic institutions”.
However, Mrs May did promise to “engage constructively” and set aside government time for indicative votes to be held.
“I must confess that I am sceptical about such a process of indicative votes,” she said.
“When we have tried this kind of thing in the past, it has produced contradictory outcomes or no outcome at all.
“There is a further risk when it comes to Brexit, as the UK is only one half of the equation and the votes could lead to an outcome that is unnegotiable with the EU.
“No Government could give a blank cheque to commit to an outcome without knowing what it is.
“So I cannot commit the Government to delivering the outcome of any votes held by this house. But I do commit to engaging constructively with this process.”
She warned MPs that if they did not accept her Brexit deal, and continued to insist that no deal was unacceptable, then a longer extension to Article 50 was likely, keeping the UK in the EU beyond European elections in May.
She also met for an hour with Labour leader Jeremy Corbyn in her Commons office.
The two leaders had a "frank and comprehensive exchange of views", a Labour spokesman said.
Mrs May suggested the Withdrawal Agreement setting out the UK’s exit terms from the EU could be “separated” from the Political Declaration, which provides a blueprint for future trade talks, but this was rejected, the Labour spokesman added.