S4C's chief executive was sacked as a "casualty" of a management breakdown, MPs have been told.
The vice-chair of the S4C authority, Rheon Tomos, said Iona Jones had to go in July after the Welsh TV channel's governing body reached an "impasse".
He told MPs on the Welsh affairs committee at Westminster the body believed it couldn't scrutinise its management effectively.
He also denied former chair John Walter Jones was bullied into resigning.
Mr Tomos told the official inquiry into S4C that the authority had unsuccessfully demanded information from the channel's board of directors on several occasions.
A corporate governance review carried out by its in-house auditors early this year recommended a fundamental change in the way decisions were taken.
In July this year, the authority decided to make the changes but the S4C management board wanted to continue with a system that separated day-to-day management from the governing body.
Mr Tomos told the committee at Westminster: "There was therefore a total impasse because we didn't feel our scrutiny role was being carried out in an effective way.
"One of the casualties, yes, of that decision was that the chief executive - her employment was terminated."
He said S4C management were not providing the authority with sufficient assurances in the conduct of its scrutiny role.
"The authority tried to demand information on several occasions but unfortunately it didn't happen, it just didn't happen."
Mr Tomos said Iona Jones was sacked by a majority vote of the authority.
Arwel Ellis Owen, the interim chief executive, denied that he was in the S4C building at the time of Ms Jones's sacking.
Solicitors advised the authority not to comment on the decision to sack Ms Jones.
Mr Tomos also admitted that there had been discussions between John Walter Jones and other members of the board before his resignation but denied that he bullied him out.
Giving evidence, Mr Tomos said that Mr Jones "had undermined his position as chairman through his actions", adding that his resignation "gave us far greater clarity moving forward".
However Vale of Glamorgan MP Alun Cairns challenged Mr Tomos's view and said that Mr Tomos had publicly appealed for Mr Jones to go on the CF99 programme.
Referring to the confusion over Mr Jones's initial resignation at a meeting of the authority, Mr Tomos said that John Walter Jones informed the authority that it was his intention to leave immediately.
However he explained that when he got up the next morning "it was a bit of a shock" to hear in the press that the chairman had changed his mind and was informing press that he was continuing as chairman.
Mr Owen also gave evidence to the committee and denied accusations made in a previous committee meeting that the organisation was "bloated".
He said that this was not a term he understood and in fact S4C was "a very lean and mean operation".
Discussing the relationship with the Department for Culture Media and Sport (DCMS), Mr Owen said that despite weekly contact with civil servants, the first he heard about the cuts to the funding of S4C was on BBC Radio 4 while travelling down the M4.
He added that they initiated the judicial review because S4C "were not consulted, were not informed" when the deal was struck with the BBC.
Mr Owen informed the committee that the judicial review will remain in place until the meetings between DCMS, S4C and BBC begin.
That meeting is due to start at 1600 GMT on Tuesday, and according to Mr Owen once that meeting starts "the judicial review will cease to exist".
Mr Owen said that two previous meetings had been cancelled for unknown reasons but stressed that "we are very hopeful we can come to an agreement".