International trade secretary Dr Fox is set to accuse critics of failing to face up to the tough choices and compromises needed to reach an agreement with Brussels.
The public display of support from the minister, who was involved in the Vote Leave campaign, is a further boost for the PM, after fellow cabinet Brexiteer Andrea Leadsom weighed behind her deal on Thursday.
Dr Fox is also due to outline Britain’s future global trading role in a major speech, saying it is “time to raise our sights, and acknowledge that there is a world beyond Europe, and a time beyond Brexit”.
He is expected to say: “The withdrawal agreement and the political declaration will not please everyone, and we have had some tough choices to make.
“Choices which many in parliament, on both sides of the House, are yet to face up to.
“But the deal we’ve reached will give us a firm and stable base on which to leave the EU and build this country’s global future, a future that still encompasses Europe, of course, but also the wide, fast-growing markets beyond, with all the opportunity that entails.”
Dr Fox was among a group of five cabinet ministers said to be led by Ms Leadsom, that was seeking to tweak Ms May’s withdrawal agreement before MPs vote on it on 11 December.
In a letter to constituents seen by the Daily Mail, Ms Leadsom said coming round to the PM’s plan had been a “challenging journey” for her, but it was the only deal on the table, and meant the UK would quit the bloc in March.
In his speech, Dr Fox is also due to make an appeal for unity and a healing of political divisions caused by the referendum result, adding: “In politics, we cannot always have the luxury of doing what we want for ourselves, but we have an abiding duty to do what is right for our country.”
Days after cross-government economic analysis suggested growth after Brexit would be slower than if the UK stayed in the EU, he is due to strike an upbeat tone about jobs and exports.
He will say: “At the time of the referendum, we were told that just voting to leave the EU would cause such an economic shock that we’d lose half a million jobs, our investors would desert us, and we would require an emergency budget to deal with the ensuing fiscal imbalance.
“What’s happened since? We’ve added over 700,000 jobs to the economy, with more people finding work than at any time in the past 40 years.
“This upward trajectory shows no signs of slowing.”
He is due to add: “The government has made clear that we want to take a balanced approach to the question of our future trading prospects.
“We need to maximise our access to the EU market, but without damaging our potential to benefit from emerging trade opportunities in other parts of the world.”
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