I don't recall the 29th March as Exit Day and No Deal and no Custom's Union being in the 2017 tory manifesto.
Is this the passage that Braverman is depending on?
^Following the historic referendum on 23rd June 2016, the United Kingdom is leaving the European Union. Only the Conservative Party, under Theresa May’s strong and stable
leadership, can negotiate the best possible deal for our country. In her Lancaster House Speech, the prime minister laid out the twelve principles she intends to follow in seeking a new deep and special partnership with the European Union. We have explained our
approach in the White Paper on the United Kingdom’s Exit from, and a new relationship with, the European Union, during the passage of the European Union (Notification of Withdrawal) Act, in the prime minister’s letter to the president of the European Council invoking Article 50, and in the Great Repeal Bill White Paper.^
s3.eu-west-2.amazonaws.com/conservative-party-manifestos/Forward+Together+-+Our+Plan+for+a+Stronger+Britain+and+a+More+Prosperous....pdf
The whole manifesto makes deeply ironic reading IMO