The early days of the Good Friday Agreement peace talks were filled with “disagreement, insults and invective”, according to former US Senator George Mitchell.

Senator Mitchell was speaking to Newstalk’s latest podcast, As I Remember It: Bertie Ahern & The Good Friday Agreement as the 25th anniversary of the accord approaches.

The one-time US Special Envoy for Northern Ireland is just one of the key players to speak to the former Taoiseach for the historic podcast, which launches on Thursday.

Senator Mitchell said progress was very slow after the talks got underway, with unionist parties wary of the prospect of Sinn Féin taking part.

"Some of them said, under no circumstances would they sit in talks if Sinn Féin entered them," he said.

"There was really very little progress, it was mostly just disagreement and insults and invective and allegations back and forth."

Senator Mitchell said rules were ultimately decided by the parties, not Dublin or London.

"It took us about three months to adopt a set of rules for the talks," he said.

US Senator George Mitchell in May 1993. Picture by: Allstar Picture Library Ltd / Alamy Stock Photo

"What had happened was that, when the British and Irish governments organised the talks, the two governments had prepared a set of documents which were intended to serve as the basis for the talks and the rules under which the talks would occur.

"Some of the parties objected to that.

"They felt that the political parties in Northern Ireland - there were 10 of them at that time in the talks - that they should be the ones to decide the rules and ultimately that position prevailed."

George Mitchell speaking in April 2018. Picture by: SOPA Images Limited / Alamy Stock Photo

Senator Mitchell said the process was still complicated.

"It was a long and complicated argument, but ultimately they did adopt rules,” he said.

"Although that took several months to do so.

"The talks then get underway and, as I said, they were not productive.

"There was great tension in that first summer because of the conflicts over the marching season around the celebration of the Battle of the Boyne.

"There was a great deal of violence - a lot of burnt-out cars, buildings; some people were injured.

"Some tensions were really quite high and we continued into 1997 making very little progress."

Breakthrough

Senator Mitchell said a breakthrough came in the summer.

"Then, in late spring or early summer of that year, Sinn Féin finally entered the talks," he said.

"They went through the same process that everyone else had to go through.

"I basically created a process by which the leaders of the party would enter the large meeting room in which all of the other delegates were present, and would stand up and make a strong commitment to adherence to the Mitchell Principles," he added.

As I Remember It

As I Remember It is a nine-part series that will launch on all streaming platforms this February 23rd.

Three episodes will be released each week throughout the run.

For bonus content including interviews, videos, an interactive timeline of the peace process and a full glossary off the key players head to newstalk.com/goodfridayagreement.

You can hear Episode One here:

Follow the podcast on Apple Podcasts,  Spotify and Google Podcasts

Download, listen and subscribe on the Newstalk App.