Progress to make the Police Service of Northern Ireland more representative of the communities it serves has stalled, MPs have warned.
Commanders must redouble their efforts to attract new recruits from under-represented groups, particularly those from a Catholic background, a report from the Northern Ireland Affairs Committee has recommended.
The committee report comes after its members examined the key challenges facing the PSNI ahead of the 25th anniversary of its foundation later this year.
It noted that in 2001 just 8.2% of officers were from a Catholic background but within 10 years that had risen to 29.4%, in part due to the 50:50 recruitment policy that ensured Catholic candidates and non-Catholic candidates were recruited in equal numbers.
MPs said the percentage has "largely plateaued at around 30% and not increased further" since the ending of 50:50 in 2011.
They said projections indicate that the proportion of Catholic officers is set to fall in the future, despite people from a Catholic background making up around 45% of the overall population in Northern Ireland.
Committee members said officers from ethnic minority groups and working-class backgrounds also remained underrepresented in the PSNI.
They urged the PSNI to consider setting up a cadet-style scheme and to conduct research on what barriers are limiting applications from under-represented groups.
The committee's wide-ranging report also examined the overall staffing levels in the PSNI.
Stormont has committed to funding a "recovery plan" to bring officer numbers up to 7,000 by 2028 amid repeated warnings from Chief Constable Jon Boutcher that current workforce numbers of around 6,300 are unsustainable.
The Westminster report calls for an "independent comprehensive analysis" to determine the "overall appropriate level of officer and staff numbers".
MPs also said more needs to be done to secure additional funding for the PSNI, as they highlighted that the service has faced a "real-terms budget cut since 2011".
The committee repeated one of its previous recommendations, for the UK Government to provide a ring-fenced pot of money to fund PSNI work on legacy cases.
Committee members also called on the Government to allow the PSNI to access the counter-terrorism funding stream provide to forces in England and Wales.
Chief Constable Mr Boutcher welcomed the report.
"Everyone in Northern Ireland and indeed beyond our borders should be concerned about the way police funding in Northern Ireland has failed to keep pace with other public services," he said.
Acknowledging the PSNI’s "recruitment challenges", Mr Boutcher said he wanted the service to be "representative of all communities in Northern Ireland".
"Moving through this anniversary year, we must have a debate about barriers to joining policing and explore how to collectively increase the number of applicants from all of those groups currently under-represented in the PSNI," he said.
He stressed that the PSNI required "community and political support and leadership" to address the representation issues.
The Police Federation for Northern Ireland, which represents rank and file officers, gave a "guarded welcome" to the report.
Federation chairman Liam Kelly said: "This report adds weight to the case we’ve been making on the need for proper funding for the service.
Mr Kelly said there was a requirement for "at least 8,000 officers" in the PSNI.
He added: "I, too, would like to see more Catholics joining the PSNI.
"The suggestion of a cadet-style scheme might possibly go some way towards addressing the issue.
"However, until there’s unequivocal support from nationalist communities, politicians, civic, Church and sporting leaders, we will face an uphill struggle to boost numbers.
"There must also be a specific recognition of the risk that continues to be posed by republican terrorists as we saw with (recent) attacks on Dunmurry and Lurgan stations.
"The response to this report by the Secretary of State (Hilary Benn) will be interesting, particularly on the question as to why Northern Ireland with its persisting threat from terrorism and paramilitary activity, is unable to access counter-terrorism funding that’s provided in England and Wales."
