Speaking to the Sunday Times, the former Fine Gael leader said that Irish politicians negotiating with the UK were uncertain whether their phone calls were being listened-in on by the UK.

He also said he was motivated to avoid a hard border due to the legacy of his party with the anti-Treaty side of the Irish Civil War.

Mr Varadkar has been speaking to different press outlets in recent weeks ahead of the publication of his memoir, Speaking My Mind.

Leo Varadkar: Speaking My Mind

Leo Varadkar: Speaking My Mind

Mr Varadkar was the Taoiseach when negotiations over the impact of Brexit began after 2016. His initial partner in these discussions was then-UK Prime Minister Theresa May.

He recalled a period when her officials placed a “huge, green tent-like object” in a negotiating room, to allow Mrs May to “make calls without being heard”.

The Sunday Times reports Mr Varadkar saying to Mrs May: “That’s an interesting piece of equipment,” before adding, “we don’t bother with any of that”.

“According to Varadkar, May responded with a wry smile: ‘Oh, we know you don’t.’”

Mr Varadkar also told that paper: “What I said in the book, and this is what I really meant, is that we did not know whether or not we were being listened to but we knew they had the capabilities to do so.

Former Prime Minister Theresa May

Former Prime Minister Theresa May

“A lot of other governments have the capacity to listen to their friends and enemies. I thought it was much smarter to act on the basis that they could be. So there were no secret strategies, because we wouldn’t necessarily have been able to keep them secret.”

He said Mrs May’s comments were not “confirmation or anything” that Irish communications were being listened to, adding: “It was an interesting contraption.”

Boris Johnston’s takeover of the premiership did not “displease” the former Taoiseach, as he felt Mr Johnston was a “more flexible” and “less principled” negotiator than Mrs May.

Boris Johnston

Boris Johnston

Mr Johnston reportedly told Mr Varadkar in 2019 that a deal was in both their interests as the two leaders were preparing for elections.

Mr Varadkar also spoke about his concerns that Brexit could result in a hard border between the two different jurisdictions on the island of Ireland.

He said he was prepared to “defy” the European Commission if they pushed such an idea, and would have been willing to take it to court to fight it.

Leo Varadkar

Leo Varadkar

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He was motivated in part by the legacy of the split in Irish politics caused by the Irish Civil War. The party he led, Fine Gael, evolved from the anti-treaty faction and has often been criticised for the consequences of the Anglo-Irish Treaty, such as the partition of Ireland.

Mr Varardkar told the Sunday Times: “I wouldn’t make their lies true a hundred years later. If necessary, I would defy the European Commission — even force it to take legal action against us. I would demand a compromise or a better deal.”