Mr Webster is understood to have given his notice at the end of last week to Cleveland Police and Crime Commissioner Matt Storey.
Mr Storey said he had recently agreed a short contract extension to allow time for a successor to be recruited and Mr Webster would remain in post until the early summer.
He said: “Whilst we are incredibly sad to see him go, Mark has earned himself a well-deserved break after three decades of dedicated police service.”
The force hasn’t commented on the pending departure of Mr Webster with Mr Storey revealing the news in an e-mail to force stakeholders seen by the Local Democracy Reporting Service.
Mr Webster was appointed in April 2022 by former PCC Steve Turner after being announced as the preferred candidate to replace Richard Lewis, who left in December of the previous year to become chief constable at Dyfed-Powys Police.
He was previously deputy chief constable at Cumbria Police and a former director of operations at the National Crime Agency.
His police career began with Greater Manchester Police in 1992, where he rose to become a senior detective during a period which saw major conflict between the city’s crime gangs.
Announcing his appointment at the time, Mr Turner described Mr Webster as a “talented and dedicated police leader with a wealth of experience in operational policing”.
Mr Storey’s e-mail said Mr Webster had accrued almost 34 years of police service and he took up his post at an “extremely challenging time” in the force’s history.
He said: “He has provided authentic and inclusive leadership to not only remove Cleveland Police from ‘special measures’, but to create the stability and structure needed to see the force make significant improvements.
“I am grateful for the high standards of professionalism and determination he has demonstrated, which leaves behind a legacy of reignited positivity that Cleveland Police will become one of the most improved forces in the country.
“Whilst we are incredibly sad to see him go, Mark has earned himself a well-deserved break after three decades of dedicated police service.
“Mark has fulfilled his three-year contract to serve as our chief constable and recently agreed to a short extension, to allow me time to recruit his successor.
“This speaks to his commitment to do the right thing for the force and the people of Cleveland.
“I will be working with the College of Policing and a range of stakeholders in the coming weeks to develop a robust recruitment process to find Cleveland Police’s next leader.”
Mr Webster overcame a tricky start in dealing with a force still in special measures and being blasted as “completely anonymous” after declining initial invitations to the Cleveland Police and Crime Panel.
There were also early doubts about his commitment to the role after it was revealed he was living outside of the area and claiming for occasional hotel stays.
But after the force began to make improvements in a bid to rid itself of the label of being the worst performing force in the country, he was praised as bringing “greater stability” by HM Chief Inspector of Constabulary Andy Cooke.
The force had been subject to enhanced monitoring by the police inspectorate after a 2019 report saw it graded as inadequate in all areas, described as “rudderless and clueless”.
In September 2023 it was moved out of the engage monitoring process after making further improvements with Mr Webster praised by Mr Turner as providing “outstanding leadership and unwavering dedication”.
Nonetheless, the force only rated ‘good’ in one of ten policing areas that were inspected with major concerns remaining about its inadequate performance in reducing and investigating crime and keeping people safe.
In an interview in 2023, Mr Webster was asked how long the public of Cleveland would have to wait for an excellently performing police force.
Mr Webster said: “The force has faced issues for the best part of a decade, if not more, you can’t turn that around in a year.
“We have made some real significant progress and the next 12 months is what I am focused on and we can really accelerate things.
“A stable leadership team, geographic ownership, dedicated commanders, more proactive policing, deal with non-policing demand, and I think we can make a massive difference.
“In another year or so after that the force is going to be in a different position.”
The LDRS understands the outcome of another force-wide inspection is expected in the first half of the year.
At a meeting last month Mr Webster claimed the force had built “solid foundations” with total recorded crime, as at December last year, being down 9.3% and at its lowest for five years.
But public confidence in the force has remained stubbornly low with residents sometimes highlighting how some crimes go unreported and giving examples of poor police responses.
And while charge rates in the vast majority of crime categories are above the national average, previous figures showed overall only about one in ten crimes recorded by Cleveland Police are solved, termed a positive outcome.
There have also been other bumps in the road.
In January His Majesty’s Inspectorate of Constabulary and Fire & Rescue Services (HMICFRS) said the force also needed to “urgently improve” how it investigates cases of children being exploited online, along with its response when youngsters go missing, both aspects being graded as inadequate.
Nonetheless, Mr Webster has been seen as a solid, capable pair of hands with evidence showing the force is on the right track under his stewardship and his departure will be seen by many as a setback for Cleveland Police, which in recent years has had something of a revolving door of chief constables.
