Baroness Arlene Foster has branded the decision to rule out a border on the island of Ireland during Brexit negotiations as a “mistake”.

On the BBC Surviving Politics with Michael Gove podcast, Baroness Foster criticised two past UK Prime Ministers in Theresa May and Boris Johnson for their role in the agreement that saw the UK withdraw from the EU.

Gove – who stood down as an MP ahead of July’s general election – spoke to the former First Minister of Northern Ireland about managing a party.

They began by touching on her decision to leave the UUP for Ian Paisley’s DUP.

She described 1998 and the signing of the Good Friday Agreement as a “very difficult time for unionism”.

Baroness Foster said she stayed with the UUP for a number of years after in a bid to make sure the peace agreement delivered for unionists but “that didn’t happen because we didn’t have decommissioning from the IRA and that caused a whole load of difficulties”.

Now a broadcaster, the former politician explained that she joined the DUP when it was “making gains”, proudly telling Mr Gove: “I’ve only ever been in the largest party within unionism, whether it was the Ulster Unionist Party or the Democratic Unionist Party.”

She added: “Because the point of a party is, it’s a vehicle to deliver for people, and for me the union has always been the most important piece about my politics and that’s why I felt I needed to move at that time.”

She spoke of the DUP being “rebuffed” by Theresa May during Brexit negotiations, saying that it was a “frustrating” period.

When asked if there was a difference between what the former Prime Minister thought she was achieving and the reality on the ground, Baroness Foster said: “Yes, I think she made a mistake in her understanding of Northern Ireland.

“This idea that there could be no border on the island of Ireland, when of course we have a monetary border, we have a taxation border, we’ve always had a border with the Republic of Ireland, ask the people who smuggle across it.

“So the idea that there wasn’t going to be a border on the island of Ireland was a mistake. And it could have been dealt with alternative arrangements, which were put forward and they were dismissed, which was wrong.”

When Boris Johnson became Prime Minister, he showed a willingness to engage “more” with the DUP but Baroness Foster said “he again misunderstood what was going on” but the parameters of a deal “had been set by Theresa in 2017, and that was the problem, and he felt constrained by that”.

She added: “But that doesn’t change the fact he let us down, he let us down really badly. He knows that. He knows that full well.”

During the podcast the former First Minister also touched on the “trigger” for DUP colleagues moving against her came about because of the Brexit deal and issues around Covid.

“The final straw,” she said, “actually, was a non-binding vote, would you believe, on conversion therapy in the Assembly.

“And I was aware that one of our members had a daughter who was gay and in an attempt to try and diffuse the situation, I said, ‘well, we’ll just abstain’.

“But by saying just abstain, people got very angry about that and that was the trigger then for my removal which came just a week later.”

Because of Covid and remote working, the former DUP leader said she “didn’t see it coming” as nobody came to her and suggested standing down, but instead rounded up signatures on a letter for a vote of no confidence.

“It was more hurtful actually from people who had signed the letter who I had went out of my way to help in the past,” she said.

“It’s always the people who you don’t expect who are more hurtful.”

She spoke of facing social media abuse, saying it got to a point where she didn’t look at them and staff had to handle them, by reporting threats if necessary.

It is a “worrying trend” for women in politics, she explained, and it does “put women off”.

News Catch Up: Monday 21st October