Plan A has not proved popular with politicians with Parliament and Senedd urging the WRU to stay with four teams.
After Tierney and Collier-Keywood gave evidence in front of a parliamentary committee in January, the politicians said the WRU had an immense disconnect with fans.
After the Senedd session, the Welsh-based politicians stated the governing body ‘had lost the argument’.
“This was always going to be difficult,” said Tierney. “Everybody said as part of the consultation we couldn’t keep doing what we were doing.
“There was a view going to three teams was the best answer as part of that.
“At the point when people start to realise what that might mean for their team and location, that’s when it gets difficult.
“It doesn’t mean it’s not the right answer.”
The WRU are also undergoing the process of selling Cardiff with Ospreys owners, Y11 Sport and Media, named as the preferred bidder.
That has raised concerns from Swansea Council about the future of professional rugby in Swansea, with the Ospreys due to move into a redeveloped St Helen’s ground.
They have begun formal legal proceedings against the WRU in a bid to stop the proposed sale of Cardiff Rugby, claiming the deal would breach UK competition law and undermine the governing body’s restructuring process for the professional men’s game.
Tierney says the deal with Y11 and Cardiff has not been completed yet with the “period of exclusivity” continuing.
She also says Y11 buying Cardiff does not mean the Ospreys will necessarily cease as a professional entity to help go to three sides.
Supporters fear this scenario and Swansea Council claim they have been told this will happen.
“Those two processes are separate,” says Tierney.
“We did an open, transparent process for Cardiff and Y11 was the best bid we received.
“When the process is completed, we will either recommend to the board we proceed with Y11 buying Cardiff, or say we don’t.
“At that point, we’ll make a decision on what happens next, but there’ll be a separate process. So just by Y11 buying Cardiff, doesn’t mean Ospreys go.”
Tierney declined to comment when asked whether she felt politicians were electioneering with Wales going to the polls in two months.
The WRU is also facing legal action from Scarlets over the governing body’s handling of the takeover of Cardiff.
That process was revealed by Llanelli assembly member Lee Waters in the Senedd hearing, with Tierney refusing to comment.
She acknowledged there is a lot of money being spend on legal battles.
“I’m a historian by training and I look at the past 20 years in Welsh rugby and the fighting that’s gone on,” said Tierney.
“I think we risk destroying ourselves. If we could put that energy and money into pulling together and being a stronger union, all that passion, hurt and anger could go into making rugby better.
“It is damaging, and it’s money, but also time and energy.
“While we’re doing that, we’re not focusing on rugby.
“I won’t comment on the exact costs, you’ll see them in the annual report.
“They’re very significant and that money is not going into rugby.”
