So you want to play hardball, Mr Trump? Mexico is to consider revoking a series of treaties – including the 1848 agreement that transferred half its territory to the United States – if the Republican candidate wins the presidency and rips up the North American Free Trade Agreement, according to a Bill to be presented to Congress.

The initiative, to be proposed on Tuesday by Armando Ríos Piter, a left-wing senator, follows last week’s much-criticised meeting between Mexican president Enrique Peña Nieto and US presidential contender Donald Trump, which inflamed public opinion and sparked a cabinet rift.

Mr Peña Nieto has faced a fierce backlash at home over what many saw as his red carpet treatment of Mr Trump, who has branded Mexicans rapists and wants to build a border wall that he insists Mexico will pay for.

“This is the first step towards establishing a public policy about how Mexico should react in the face of a threat,” Mr Ríos Piter told the Financial Times.

“This [Bill] is simply to protect a successful 22-year-old relationship [Nafta] that has helped both nations,” he said. “We want to defend that from a position that seeks to destroy it. We have to put it in black and white.”

The initiative would make it illegal for Mexico to use official cash to fund the building of a border wall. If Mr Trump attempted to seize the $24 billion (€21.5 billion) in annual remittances from the US to Mexico to pay for it, the Bill would empower Mexico to retaliate in kind by impounding the same sum, probably through a tax on remittances heading in the other direction.

Furthermore, if Mr Trump made good on threats to scrap the 1994 Nafta free-trade deal – credited with creating one in three jobs in Mexico – it would call for a review all 75 bilateral treaties between the two countries to establish if they were in the national interests.

– (Copyright The Financial Times Limited 2016)