The original complaint that led to the BBC’s Naga Munchetty being disciplined over her comments about Donald Trump was also about her co-host, Dan Walker, according to correspondence seen by the Guardian, in apparent contradiction of the corporation’s assertion that there had been no complaint about his role.

After the BBC ruled last week that Munchetty had breached editorial guidelines in a conversation with Walker about Donald Trump, the corporation defended itself against anger that only a woman of colour had been punished and not her white, male co-host by insisting its hands were tied.

The BBC’s editorial standards chief, David Jordan, twice suggested in interviews that the high-level executive complaints unit was able to consider only Munchetty’s role in the segment even though Walker made similar points and asked the questions prompting her remarks because she was the sole subject of the complaint.

“The simple fact is we haven’t had a complaint about Dan Walker’s role,” he said in one interview. “The complaint was about Naga Munchetty.”

But the Guardian can reveal that the original complaint from a member of the public described Walker as “very unprofessional” and accused him of “repeatedly expressing incredulity” that anyone could defend Trump over his remarks urging four Democratic congresswomen to “go home”. A second message after the first complaint was rebuffed also referred to Walker’s conduct.

The BBC did not dispute the content of the original complaints. But it argued that when the viewer was given the opportunity to appeal to the executive complaints unit, they were asked to clearly and concisely set out why they remained unsatisfied.

A spokesperson said this third version of the complaint “specifically focused on Ms Munchetty’s comments rather than Mr Walker’s, which is why this was the focus of the ECU investigation”.

With the text of the original complaint circulating at the organisation, the decision has created an open rebellion among BBC staff, with some demanding why a woman of colour was punished and not her white, male co-host.

One senior BBC journalist said there was fury at the decision: “They’ve chosen to interpret the complaint as only being about Naga and made her a sacrificial lamb. The process is a mess. David Jordan has led two programmes to believe that the complaint wasn’t about Dan Walker, when it clearly was.”

The disclosure of the language in the original complaint, filed with the subject line of “Blatant political bias from both presenters”, will increase pressure on Jordan and amplify calls for fresh scrutiny of the editorial complaints process.

The message made clear that the viewer felt Walker “repeatedly expressed incredulity” about Trump’s tweets and “very unprofessionally” asked Munchetty for her personal views on the issue.

The original complaint said: “Dan Walker, whilst interviewing a guest about President Trump’s recent tweets regarding 4 Democrat politicians in the USA, repeatedly expressed incredulity that anybody could defend Trump’s tweets. Very unprofessionally, he then asked his fellow presenter Naga Munchetty for her personal opinions on this news story! She foolishly complied with his request and launched into an attack on Trump, including stating that she was personally ‘furious’ about his comments.”

It continued: “These two presenters have never made any secret of their left-wing and anti-Trump bias but usually in more subtle ways, such as eye-rolling and looks of exasperation when reporting on news stories. However, personal commentary on controversial news stories is surely going too far and is way outside of their remit. They are employed as presenters not political commentators and as such should at least feign impartiality. It’s about time they were reminded of this.”

Facebook Twitter Pinterest David Jordan: ‘The simple fact is we haven’t had a complaint about Dan Walker’s role.’ Photograph: PA Wire/PA

The BBC initially defended Munchetty, saying she “made it clear that she was making a general point and not accusing anyone of anything”.

The viewer responded by sending a second complaint, asking for it to be investigated further and again referring to both presenters: “Dan Walker asked Naga Munchetty to comment SPECIFICALLY on the SPECIFIC tweet sent by a SPECIFIC person (President Trump). She said that she was SPECIFICALLY “furious” about the SPECIFIC words used by that SPECIFIC person in a SPECIFIC tweet.”

“This could not possibly be construed as the making of a ‘general point’ by any reasonable person. I would like my complaint to be investigated again and a more honest reply sent please. If you are content for your supposedly impartial presenters to make biased political statements, just say so. If you are not, then my complaint should be upheld and words of advice given.”

Jordan’s defence of the corporation has relied on the claim that the viewer was solely concerned about Munchetty’s conduct. In an interview with Radio 4’s Today programme on Friday, its editorial standards chief said Munchetty was “led down that path unfortunately by her co-presenter [Walker] as you heard on that clip”.

Presenter Nick Robinson replied: “Well, that raises the question some have asked – I don’t want to get our fellow presenter into trouble – they say: well, why pick her out, if they’re both guilty of it?”

Jordan replied: “Well, I’m afraid the executive complaints unit can only deal with the complaints that it receives.”

On the corporation’s Newswatch programme, Jordan said: “I am afraid the executive complaints unit deals with the complaints it gets. Some people have said why isn’t Dan Walker being singled out in the same way as Naga Munchetty? The simple fact is we haven’t had a complaint about Dan Walker’s role.”

“The complaint was about Naga Munchetty.”

He continued: “They’re obliged to deal with the complaints they have, not the complaints they might like to have or complaints that might be available.”

A spokesperson for the broadcaster said: “The appeal to the ECU focused on comments by one presenter, but the statement from the executive team on Friday is clear – the BBC is not impartial on racism. Racism is not an opinion and it is not a matter for debate. Racism is racism. Naga has the very clear support of the top of the organisation.”