Police chiefs have warned of the dangers of using unpaid volunteers to replace fully-trained officers as figures showed police numbers were at their lowest for nine years.
The number of officers in the 43 forces across England and Wales fell 3.6% to 134,101 in the year to the end of March, while the number of special constables rose 10.4% to 20,343, Home Office figures showed.
Chief Superintendent Derek Barnett said that while special constables, who are unpaid volunteers, carried out valuable work, they must not be used to replace fully-trained and professional full-time officers.
"Events in London and elsewhere last summer and more recently in the run-up to the Olympics have seen the value of having a police service that is fully trained, equipped and sufficiently resilient to respond to any eventuality to protect the public," he said.
Mr Barnett, president of the Police Superintendents' Association of England and Wales (PSAEW), added: "I pay tribute to the valuable work of the men and women who volunteer as special constables, and welcome the increase in their numbers.
"But they must not and nor should they ever be seen as a replacement for fully trained and professional full-time police officers."
Some 5,009 officers were lost in the year, meaning there were now fewer full-time officers than at any point since 2003, the figures showed.
The number of police staff was also down, dropping 8.8% to 67,474, while the number of police community support officers (PCSOs) also fell, down 9% to 14,393.
Shadow home secretary Yvette Cooper said the government had now cut nearly 10,000 officers from communities across the country.
"We know that substantially more than half are from 999, neighbourhood and traffic response - the officers we rely on in an emergency," she said.
"These figures show the cuts to the police are deeper and faster even than experts predicted.
"David Cameron's promise to protect the front line has been ripped apart by these appalling figures.
"In just two years the government has taken police numbers back by nearly a decade, weakened police powers, undermined morale and reduced crime prevention.
"Theresa May has no strategy to cut crime, only to cut police."
But Policing and Criminal Justice Minister Nick Herbert said the reductions were in line with what Her Majesty's Inspectorate of Constabulary (HMIC) predicted as a result of "necessary savings".
"HMIC projections also showed that 94% of officers in the front line will remain, the proportion on the front line is increasing and service to the public is largely being maintained," Mr Herbert said.
"We inherited a situation where there were some 25,000 officers not on the front line, so there was plenty of scope for forces to make savings while improving performance, as forces are showing as they continue to drive down crime."
The biggest drop in officers came in Derbyshire, where police officer numbers fell 10% from 2,021 at the end of March last year to 1,819 12 months later.
Warwickshire, where officer numbers fell 8.2% from 919 to 844, and Cleveland, where officer numbers fell 7.6% from 1,655 to 1,529, also saw significant reductions.
Only Surrey has seen an increase in its number of officers, rising 4.7% from 1,885 to 1,974.
Simon Duckworth, chairman of the Association of Police and Crime Commissioners' Transitional Board, said: "The public will always be concerned by drops in officer numbers, but it should be of some reassurance that these stark figures are falls from historic highs and that, thanks to the dedication of the police service, crime continues to fall.
"It is clear that rising police numbers over the last decade were accompanied by some dramatic drops in crime.
"Though the police will remain focused on the front line, those voting for Police and Crime Commissioners (PCCs) in November will require reassurance that further falls in police numbers won't jeopardise hard-won gains in keeping them safe."