Speaker John Bercow is the victim of a "witch-hunt" by disgruntled former staff seeking to discredit him, a senior House of Commons official has said.
Mr Bercow has faced calls to quit over allegations - which he emphatically denies - that he bullied two former private secretaries.
But Serjeant-at-Arms Kamal El-Hajji said many current members of Commons staff were united in regarding the claims as a witch-hunt against the Speaker.
And he said that he personally appreciated the support and guidance given to him by Mr Bercow since his appointment as the first person from an ethnic minority background to hold the position of Serjeant-at-Arms, with responsibility for keeping order within the Commons.
Writing in The House magazine, Mr El-Hajji said there had been a slew of accusations about the Speaker's conduct and his treatment of staff and colleagues.
But he added: "Due to a considerable lack of evidence supporting these allegations, it seems clear to me that there is a witch-hunt against him, whether it is coming from previously disgruntled staff members or ex-colleagues trying to settle old scores of some kind."
Mr El-Hajji said he had discussed the allegations with "numerous" current staff and senior officials at the Commons.
"We share the same view - we feel that there is a witch-hunt going on, trying to discredit Mr Speaker," he said.
Mr El-Hajji said his work in the Commons had "not been very easy" since his appointment to the 600-year-old role in 2015.
"It certainly felt like there were a lot of unhappy people because of my appointment, and the only viable explanation I can think of is that I am from an ethnic background," he wrote.
"The support and guidance that Mr Speaker has showed me since I started is probably one of the main factors behind why I am still fulfilling this very prestigious role today.
"Parliament has never in its history enjoyed the inclusion and diversity that it does today, and this is thanks to Mr Speaker's drive to make Parliament a place for talent, regardless of race, gender, religious beliefs, disability or any other sort of discriminatory factor."
And he added: "I felt it's important to stand up for what is right and to show support and solidarity to someone who has done such a great deal for Parliament and for the country."
Angus Sinclair, who served as Mr Bercow's private secretary from 2009-10, went public with his complaints last month, accusing the Speaker of "over-the-top anger", shouting, swearing and intimidation.
Similar allegations of bullying have also been raised in relation to Mr Sinclair's successor, Kate Emms, who left the post after just nine months in 2011.
But a committee of MPs and lay members last month blocked an investigation by the Parliamentary Commissioner for Standards.