John Bercow has told friends he intends to stand down as Commons Speaker next summer, the BBC understands.
His departure, in June or July, would coincide with his tenth year in office.
The news comes after a damning report on the failure of high level figures in Parliament to deal adequately with bullying of staff at Westminster.
Dame Laura Cox's report condemned a culture in which abusive behaviour was "tolerated and covered up", prompting calls for Mr Bercow to quit right now.
Speaking in the Commons, Former Tory cabinet minister Maria Miller told Mr Bercow a "complete change in leadership" was needed at the top of the parliamentary authorities "including you".
One of Mr Bercow's critics, Tory Andrew Bridgen, said his announcement was a "pre-emptive strike to head off calls for him to go immediately" and another, James Duddridge, said it was a "smokescreen" and the Speaker was "not fit" to lead an overhaul of Commons working practices.
The BBC understands from well-placed sources the Speaker has told friends and close associates he is still considering how and when to announce his departure.
"He doesn't want it to look as if he's been forced out," said one. "But it may be it won't be enough, and some people will insist he goes much sooner."
Approached for a comment on the Speaker's plans, a spokeswoman said: "The Speaker was elected by the House in 2017 for the course of the Parliament. In the event he has anything to say on his future plans, he will make an announcement to the House first."
When he took the job in June 2009, Mr Bercow said his intention was to quit by June of this year, after nine years in the chair.
He has since said he means to stay on and see Parliament through the process of Brexit, which is due to conclude with the UK's exit on 29 March 2019.
Mr Bercow, a former Tory MP who represents Buckingham, has denied claims he bullied two of his former private secretaries - claims which MPs opted not to investigate earlier this year.
Although Dame Laura did not investigate individual cases, she said highly-placed figures should consider whether they could change the culture in Parliament and, if not, "consider their position."
Speaking in Parliament earlier, Mr Bercow called for an independent body to be set up to investigate allegations, telling MPs they should learn the lessons of the expenses scandal, which led to external oversight of financial claims.
The new regulator, he said, should be able to decide whether historical cases dating back many years could be investigated - something not currently allowed.
'Part of the problem'
But a number of MPs said Mr Bercow, who is already the longest-serving Speaker since World War Two, was not the right man to oversee the changes and should make way.
Mr Bercow's three predecessors, Bernard Weatherill, Betty Boothroyd and Michael Martin, each spent between eight and nine years in the role.
The Cox report, announced in March after a wave of allegations of inappropriate behaviour by MPs and ministers in late 2017, details alleged sexual harassment of women who say they were "inappropriately touched" and "repeatedly propositioned".
There were reports of men trying to kiss women "grabbing their arms or bottoms or stroking their breasts or bottoms".
Staff reported men putting their arms around women's shoulders or waists or "pulling them into corners for close personal contact".
A senior figure has described the atmosphere within the Parliamentary senior establishment as akin to "panic" in the aftermath of the report.
The complaints system set up three months ago now seems likely to be opened up to previously excluded historical complaints against MPs - potentially inviting a fresh wave of politically and personally embarrassing allegations.
In the climate of recriminations and counter-recriminations, a source in Parliament blamed government whips - in both main parties - for pressing to limit the range of admissible complaints in the past. "They wanted to use the information privately to help control their MPs."
Commons leader Andrea Leadsom said the new complaints procedure was working well but it was "far from job done" and harassment must be "stamped out" completely.
"The idea that just scalping one man is going to improve the culture in parliament is laughable" - Jess Philips MP on calls for the Speaker John Bercow to resign now#newsnight pic.twitter.com/4qHWxiczOJ— BBC Newsnight (@BBCNewsnight) October 16, 2018
Several MPs have warned that the issue of inappropriate behaviour in the Commons must not be politicised in partisan wrangling over Mr Bercow's own future.
The speaker is likely to play a key role in parliamentary debates over Brexit in the coming months, leading one senior Labour figure to claim it was not the "right time" for any change.
Green MP Caroline Lucas called for "independent processes, not innuendos" while Labour's Jess Phillips said she, unlike other MPs, had actually spoken to those affected by bullying.
"Some of us don't actually care who is the offender, it is the victims we care about.
"We will not use it for political gain. Nothing fills the victims with more dread than when people play with their feelings so don't do it."
However, others warned against a witch-hunt, with ex-Conservative minister Sir Desmond Swayne saying most MPs acted "perfectly properly" and were not treated like "demi-gods" by their staff.