Simon Byrne has resigned as chief constable of the Police Service of Northern Ireland (PSNI) with immediate effect.
Policing Board members accepted his resignation on Monday, four years after he was appointed to Northern Ireland’s top policing job.
In a statement, Mr Byrne said it was “now time for someone new to lead this proud and resolute organisation”.
Pressure had been mounting on Mr Byrne following a number of controversies.
Last Tuesday a court ruled two junior officers were unlawfully disciplined following an arrest at a Troubles commemoration in February 2021.
The event was marking the anniversary of the 1992 Sean Graham bookmakers attack where five people were murdered by loyalist paramilitaries.
The judge said the officers were disciplined to allay any threat of Sinn Féin abandoning its support for policing in Northern Ireland. Sinn Féin has denied this.
Mr Byrne said he was considering an appeal against the ruling.
Last month a number of data breaches came to light, including one where the names and details of the PSNI’s 10,000 officers and civilian staff were published in error as part of a Freedom of Information request.
‘Fear and uncertainty’
Mr Byrne later said the information was in the hands of dissident republicans, who could use the list to generate “fear and uncertainty”.
Some of the information included the rank or grade of employees, where they are based and the unit in which they work.
This led to some staff saying they fear for their safety due to continuing threats from paramilitaries.
An independent-led review is due to be carried out into the breaches.