The Prime Minister has released a new code of conduct for Conservative Party representatives, following a string of sexual harassment allegations at Westminster.
As part of the code, the Tories are immediately adopting a new complaints procedure with a new hotline for reporting potential breaches and a more detailed process for investigation by a panel, which will for the first time include an independent member.
In a letter to Commons Speaker John Bercow, Theresa May said the Government and her party believe there should be "a common, transparent, independent grievance procedure for all those working in Parliament who wish to raise concerns which provides clarity and certainty about how their concerns will be dealt with, and the support they will receive".
When allegations of sexual misconduct first began circulating last week, ministers were warned that "serious action" would be taken by Mrs May where necessary.
A list of MPs accused of inappropriate behaviour has reportedly been circulating at Westminster.
In her letter, Mrs May said there was a "vital need to provide better support and protection for the thousands of staff working in Westminster and in constituency offices across the country".
She called on other leaders to help her deliver a "serious, swift, cross-party response" to the problem, which would allow complainants to take their concerns to a single body, regardless of the party of the alleged offender.
The 61-year-old appeared to rebuff Mr Bercow's suggestion that policing MPs' behaviour should in the first instance be a responsibility for the political parties, pointing out that some MPs have no party affiliation - including the Speaker himself.
"It cannot be right when dealing with serious issues relating to behaviour in Parliament that vulnerable or concerned people are expected to navigate different grievance procedures according to political party," said Mrs May.
"Neither can it be right that such difficult issues themselves are dealt with on a party political basis, or that no support should be provided for those with no political or party affiliation."
The new code of conduct will apply to representatives including MPs, MEPs, peers, members of the Scottish Parliament, Welsh Assembly and Greater London Assembly, Police and Crime Commissioners, elected mayors, councillors and officials.
Under the new code, an email address and confidential phone hotline for cases where individuals feel unable to resolve their complaint informally with the person involved will be provided.
It also sets out a three-stage process for dealing with complaints, beginning by collecting information from the complainant and any witnesses and giving the alleged offender an opportunity to reply.
This information will be assessed by a panel of three or more people appointed by the party chairman and including at least one independent member.
The panel will report their findings to the chairman, who may refer the case up to the leader or party board.
Where complaints are upheld, individuals may be suspended or expelled from the party, and the panel may also contact police direct in relation to allegations of criminal wrongdoing.
The code states: "When we receive a formal complaint, we will investigate it in a timely and confidential manner. The investigation will be conducted by someone with appropriate experience and no prior involvement in the complaint.
"The investigation should be thorough, impartial and objective, and carried out with sensitivity and due respect for the rights of all parties concerned."
On Wednesday, Sir Michael Fallon quit as Defence Secretary, admitting his behaviour had "fallen below the high standards required" in his role.
The shock announcement came after it emerged Sir Michael had repeatedly put his hand on a female journalist's knee at a dinner in 2002.
As well as apologising for his actions the 65-year-old acknowledged that what might have been acceptable in the past was no longer appropriate.
Meanwhile, Labour MP Kelvin Hopkins, 76, was suspended from the party over allegations about his behaviour towards a young activist.
He has been an MP for 20 years and has remained on the backbenches except for a four month stint as culture spokesman last year.
It is understood that Mr Hopkins was spoken to about why his behaviour was inappropriate and reprimanded by then chief whip Dame Rosie Winterton when Ms Etemadzadeh made her initial complaint after dealings with the MP in 2014 and 2015.
A complaint made to the leader's office last year was based on the same information so no further action was taken.
Ms Etemadzadeh is understood to have given fresh information when she contacted the party about the allegations on Thursday.
Claims have also been made against Mrs May's de facto deputy prime minister Damian Green, which Cabinet Secretary Sir Jeremy Heywood is looking into.
It is claimed Mr Green "fleetingly" touched young activist Kate Maltby's knee during a meeting at a pub in 2015 and a year later sent her a "suggestive" text message.
Mr Green said any allegation that he made sexual advances to Ms Maltby was "untrue (and) deeply hurtful".
The department is separately probing whether international trade minister Mark Garnier breached the ministerial code after he reportedly admitted asking his secretary to buy sex toys and calling her "sugar tits".
The Conservatives' new code of conduct is due to be formally adopted at a meeting of the party's board at the end of November.
Mrs May is due to meet opposition party leaders including Jeremy Corbyn on Monday to discuss proposals to bring forward a new grievance system for Westminster.