Walker, who will step in to the role immediately, admitted that Welsh rugby was facing an "existential crisis" and the WRU needed to do "much better".

The 58-year-old Phillips had faced pressure over the organisation's handling of the issues which were raised in an investigative television programme by BBC Wales.

"It is with a huge amount of regret that I have decided to hand in my resignation," said Phillips.

"I have always had the best interests of Welsh rugby at the heart of my every action and thought, but have come to the conclusion that it is now time for someone else to lead the way.

"This is a sport I love and is so admired around the world and I wish everyone involved in the game every success and my heartfelt best wishes.

"I am absolutely aligned with Ieuan's [Evans] commitment to re-examine and further improve the cultures and behaviours at the WRU and fully support the formation of a new independent taskforce.

"I am pleased I have been able to start this process for the WRU.

"On a personal note, I wish Nigel Walker well and thank all of the dedicated staff at the WRU who can be extremely proud of the efforts and hard work they put in on a daily basis to the betterment of our game.

"I am on record already saying how much I hugely regret the feelings and emotions expressed recently by former members of staff."

Phillips' resignation comes in the wake of two women's allegations of a "toxic culture", while another former employee heard a racist term used in a work meeting.

Former head of Wales women's rugby Charlotte Wathan said she considered suicide and claimed a male colleague said that he wanted to rape her.

Amanda Blanc, who chaired Welsh rugby's professional Board between 2019 and 2021, warned the WRU of an equality and diversity "ticking timebomb".

She had recalled a "truly offensive discussion" about reducing the sanctions for an elected WRU member after he had made misogynistic comments in public, including that "men are the master race" and women should "stick to the ironing".

The allegations had led to calls for Phillips to step down and, although he apologised, he said he was still the best person to lead the WRU.

Chairman Ieuan Evans had also initially backed him to continue in the role.

Evans has said that he is setting up an external task force to review the WRU's "culture, systems and structures" with Sport Wales advising on the make up of the panel.

The WRU has stressed that no allegations were made against Phillips and he was not accused of any wrongdoing.

Walker made 17 appearances for Wales between 1993 and 1993 following an athletics career.

The 59-year-old represented Britain at the Los Angeles 1984 Olympic Games in the 110 metres hurdles where he reached the semi-finals.