You're listening to a podcast from the BBC World Service. This is Hard Talk with me, Sarah Montague.

Thanks for downloading this edition of the programme and I hope you enjoy it.

Welcome to Hard Talk on the BBC World Service. I'm Sarah Montague. In a matter of weeks,

Britain will leave the EU. And yet what happens then is still not agreed. The sticking point in negotiations is the Irish border.

How can the UK be outside the European Union, and yet there be no change to the border between Northern Ireland and the Republic?

But the Good Friday Agreement 20 years ago brought peace to Ireland in large part because it made the border invisible.

My guest today, Bertie Ahern, was Irish Prime Minister at the time of the Good Friday Agreement

and one of its signatories.

Does he really think peace is threatened now?

Bertie Ahern in Dublin, welcome to hard talk.

How great do you think is the threat to peace from Brexit?

Well, I've continually said over the last two years

that I hope that there's never any return to violence again

and that we never go back to the bad old days.

But I think we have to be aware that the idea of an infrastructural border again,

going back to customs posts, going back to police or army on the border, would really heighten fears and tensions.

The border has been controversial since the 1920s. The IRA campaign of 1956 to 62 was just the border campaign. It was centered around the border.

And of course, the more recent troubles, well, recent in terms that it was 1968, 69 on to the 1998 agreement.

That was a large part on the border too. And we know that there is, you know,

grave tensions at the moment along the border. So I still want to believe that we had no

return to violence. But I think the tensions, the animosity, the enmity, you know, the bitterness

that the hatred that bringing back any kind of an infrastructure

...