Iain Duncan Smith claimed the Irish government had set out plans to protect frictionless trade with Northern Ireland soon after the Brexit referendum. The Conservative MP revealed the plans were later scrapped after the election of current Prime Minister Leo Varadkar in 2017. The Irish border issue has since evolved into a key point of contention between the UK and the European Union.
Speaking to Good Morning Britain, the former leader of the Conservative Party said: "There is one real reason why, at the time, Enda Kenny had already started preparations for an open border without any demand.
Speaking earlier this month, Taoiseach Varadkar said the UK’s departure from the EU has “undermined” the Good Friday Agreement and it is damaging the relationship between Britain and Ireland.
Mr Varadkar said: "Brexit has undermined the Good Friday Agreement and it is fraying relationships between Britain and Ireland.
"Anything that pulls the two communities apart in Northern Ireland undermines the Good Friday Agreement and anything that pulls Britain and Ireland apart undermines that relationship."
Theresa May announced two weeks ago she had agreed to sign the UK into a backstop arrangement to ensure no hard border is formed between Northern Ireland and the Republic after Brexit. Britain would apply EU rules and standards and follow a common external tariff rate.