The House of Commons has been forced to deny claims staff work in a "culture of fear" after a report alleged bullying by MPs - including Speaker John Bercow.
An investigation by BBC's Newsnight claimed female clerks working for the Commons faced harassment or bullying and suggested that their careers suffered if they complained.
A House of Commons spokesman said it was a "responsible and supportive employer" and did not tolerate "bullying or harassment of any kind".
Newsnight conducted dozens of interviews and reviewed internal parliamentary human resources documents as part of its investigation.
The BBC programme claimed Mr Bercow had a reputation as a bully, highlighting Kate Emms' short-lived tenure as his private secretary from May 2010 to February 2011.
The programme claimed she was undermined by Mr Bercow and he appeared to frequently shout at her.
The Speaker's spokesman said: "The Speaker completely and utterly refutes the allegation that he behaved in such a manner, either eight years ago, or at any other time. Any suggestion to the contrary is simply untrue."
Allegations were also made about Tory MP Mark Pritchard and Labour's Paul Farrelly.
Clerks told the programme that Wrekin MP Mr Pritchard was "particularly nasty to those he felt were below him" and was "known for having a dreadful temper".
He allegedly swore at an official, telling her "you haven't got a f***ing clue what you're talking about".
Mr Pritchard told the programme: "I understand, over the past several years the House authorities have addressed numerous complaints about MPs, but they have also informed me they have no record of any complaints against me, and if they had, I would have been notified."
Mr Farrelly, a member of the Culture, Media and Sport Select Committee, was the subject of a formal complaint under the House's Respect policy in 2012 in relation to his treatment of clerk Emily Commander, the programme said.
The inquiry conducted by House official Edward Wood concluded there had been "an abuse of power or position, unfair treatment and undermining a competent worker by constant criticism" adding "the conduct was offensive and insulting".
But the House of Commons Commission, a panel of MPs chaired by the Speaker, could not reach a decision on what to do, Newsnight said.
Mr Farrelly told Newsnight: "In 2012 allegations were made about me having bullied a clerk to the Committee during the compilation of the phone hacking report.
"These allegations were investigated and not upheld.
"Despite this, I apologised if I had inadvertently upset the clerk who had suffered stress.
"The policy under which they were investigated was considered to be so unfair to those complained about that it was immediately withdrawn and replaced by another policy."
A House of Commons spokesman said: "We take the welfare of our staff extremely seriously, and strongly reject any claims to the contrary.
"It is a grotesque exaggeration to suggest that members of the House of Commons service work in a 'culture of fear' in relation to dealing with bullying and harassment by MPs.
"The House of Commons takes pride in being a responsible and supportive employer and does not tolerate bullying or harassment of any kind.
"In 2014 the House of Commons introduced the revised Respect policy which is specifically designed to combat bullying and harassment of House employees by MPs or their staff.
"In addition, we have implemented a range of measures to complement the Respect policy, including training for managers on how to address reports of bullying or harassment and a team of trained bullying and harassment contacts for staff to approach should they have concerns.
"We are unable to comment on any individual cases but note that the issues raised by BBC Newsnight precede the introduction of these new procedures and processes."