PSNI Chief Constable Matt Baggott is to appeal a Belfast High Court ruling that the PSNI wrongly facilitated illegal and sometimes violent loyalist flag protest marches.
A legal challenge to the PSNI's decisions was taken by a resident living in a nationalist area of east Belfast.
The legal action centred on protests that took place between December 2012 and February 2013.
They came after Belfast City Council had taken a decision to limit the flying of the Union flag over Belfast City Hall.
Mr Baggott said the PSNI had to operate in very challenging and difficult times and he believed its approach had been responsible.
A resident from the nationalist Short Strand area took legal action over the PSNI's strategy.
Lawyers for the resident argued that for a period the police had allowed "un-notified parades" to take place and failed to arrest those involved.
A PSNI Assistant Chief Constable denied in court that the police had adopted a "laissez-faire" attitude to policing the protests.
However, Mr Justice Seamus Treacy upheld the legal challenge at Belfast's High Court.
He said the police had not understood their powers over the protests.