Getting equal Catholic and Protestant numbers in the Police Service of Northern Ireland could take another decade, the force has warned.

And Deputy Chief Constable Mark Hamilton added that its role in investigating killings committed during The Troubles could be a hurdle to more Catholics joining the force.

He said: “The more we can collectively remove the barriers to this then the better. But I do think we’re probably looking at another 10 years of hard work at this at least.”

The force conceded last year’s recruitment campaign had resulted in 75% of new officers being Protestant.

His comments came as PSNI marked its twentieth anniversary with the launch of a fresh recruitment campaign to hire up to 400 new student officers.

The force will be holding a series of small-scale engagement events within communities in a bid to improve applications and run a three-week multi media campaign.

DCC Hamilton added: “During this time, we have witnessed immense change not only within our Service but also as a society.

“The theme of this campaign is ‘Make it a Career’ and that’s exactly what we want people who are considering a career in policing to do.  As we approach the twentieth anniversary of the Police Service of Northern Ireland, we want to focus on the future and the next generation of people who want to dedicate their careers to serving their local community.”

He added there was also a perception among young Loyalists that the force gives preferential treatment to Republican communities.

Last year’s recruitment comes despite Sinn Fein’s leadership joining its campaign launch with a historic message for supporters to sign up.

Dolores Kelly, the SDLP spokesperson on Policing, Victims and Legacy, said it was time to bring back the 50:50 quota recommended in the Patten Review two decades ago.

Patten had estimated it would take a decade to achieve it.

Ms Kelly said: “Catholics now make up just 32% of the police service and without action this is likely to fall even further in the years to come.

“We need to do everything we can to encourage more Catholics to join the PSNI so that we have a police service that is truly representative of our society.”

The Justice Minister warned criticism from politicians was undermining public confidence and that some were afraid to engage with officers.

Naomi Long said: “The recent narrative around the lack of confidence in policing seems to me to be based on perception rather than fact, and to be far from universal.”

She added: “People are afraid because of the political narrative to be seen to engage with policing in their community. I think what would build confidence right across this community is if we did what was envisaged in the Patten report and took politics out of policing.”