Police forces across the North East have been praised for coping with massive spending cuts.
But the comments came in a new report from official inspectors which also laid bare the scale of the cuts forces have endured.
Crime is continuing to fall and forces are protecting their front line services “as best they can”, said HM Inspectorate of Constabulary (HMIC).
But inspectors warned that forces might struggle to cope with further funding cuts.
HMIC has published a series of studies judging each force on how they dealt with grant cuts.
Northumbria Police had to save £91.9m over four years, HMIC said.
This meant losing 648 police officer posts, 763 police staff and 182 Police Community Support Officers - a total loss of 1,593 staff, just under a quarter of the force’s entire staff numbers.
The report said that Northumbria faced a particular challenge because it is more reliant on direct Government funding than other forces and less able to make up for cuts in Government grant through the council tax.
It said: “The force faces a particularly difficult challenge as it receives the highest proportion of central funding and lowest council tax precept in England and Wales. Plans are in place to achieve all savings required, including the use of reserves to smooth the transition, meeting savings while reducing officer numbers.”
But the force might be unable to manage further cuts, HMIC said.
“The plans for dealing with further austerity beyond 2016 are still developing and there are risks to the current structures should extra funding be removed nationally.”
Durham Police had to save £20.8m over four years, HMIC said, which meant losing 252 police officers, 79 staff and 17 Police Community Support Officers, a total loss of 348 staff or 13% of the total.
HMIC said: “It has a strong track record of achieving planned savings. In May 2014, it had already achieved the savings it needed to make by March 2015.”
Cleveland Police had to save £31.0m over four years, HMIC said. This included losing 333 police officer posts, 527 police staff an 48 Police Community Support Officers.
The success of the three North East forces contrasted with the failure of some to draw up plans for making the cuts needed. These included Bedfordshire, Gwent and Nottinghamshire police services.
The reports said HMIC was concerned about the erosion of neighbourhood policing. Some officers are spending more time away from their neighbourhood beats because they have more crime investigation work to do.
HM Chief Inspector of Constabulary, Tom Winsor, said: “There are still more efficiencies that forces could achieve through greater measures of collaboration between forces and with the private sector and other parts of the public sector.”
Yvette Cooper, Labour’s Shadow Home Secretary, said: “This report confirms the serious threat to neighbourhood policing.”