Only 4% of recorded assaults on frontline police result in the perpetrator being jailed.
Figures also show that just 36% of the attacks lead to a prosecution and 31% to a conviction.
The startling statistics emerged as police leaders estimate an assault on front line bobbies happens every four minutes.
Many say the justice system is failing to protect the battered thin blue line and called for more prosecutions and harsher sentences as a deterrent.
Police Federation chairman John Apter said: “Far too often I hear of the Crown Prosecution Service dropping charges... Or when offenders are convicted, they get short or suspended sentences – often meaning they can walk smirking from court.”
He said the message must be “if you assault an officer you will be jailed”.
Official figures show there were 26,295 recorded assaults on constables in England and Wales in 2018, with 9,565 being prosecuted.
Court figures reveal only 8,265 of those accused were convicted and 1,103 jailed.
These are for assaults, not more serious attacks such as GBH.
More than 1,500 were given either suspended prison sentences or conditional discharges.
Community sentences were handed to 2,800 offenders. A total of 2,427 were fined.
But there were only 280 cases where magistrates ordered attackers to pay compensation to the injured officers.
A new law came into force this year doubling the maximum jail term for thugs who assault police and emergency workers to 12 months.
Police say there are more than two million physical attacks on them every year but the vast majority are not reported.
Director of Public Prosecutions Max Hill, QC, has held talks with police chiefs to discuss their rising concern over the number of offenders charged with attacking police.
Police Federation Chairman John Apter has been spat at, punched, kicked and knocked unconscious in the line of duty.
He said: “As a society, we must make it absolutely clear we will not tolerate this type of behaviour, there must be a consequence.
“But far too often I hear of the Crown Prosecution Service dropping charges against people who have attacked police officers. Or that when offenders are convicted, they get short or suspended sentences – often meaning they can walk smirking from court. “
He added: “The message from the courts needs to be crystal clear, if you assault a police officer you will go to prison.
The CPS said: “We will not hesitate to charge this disgraceful offence if our legal test is met.”
It added the Director of Public Prosecutions has met police and “agreed a joint approach”, with “updated CPS guidance... being published shortly”.
Sergeant Stevie Bull was answering a routine call to a hospital when she was confronted by a gunman who was threatening a nurse.
Security men had gone to the wrong location during the incident at University College Hospital, central London, in March last year and Sgt Bull was on her own.
The suspect had a large suitcase and she feared it might contain a bomb.
According to her training, the officer 28, who won a Pride of Britain award, in partnership with TSB, should have backed away and waited for armed back-up.
But retreat was not an option with the life of the nurse at stake.
“I was so close to him that it was fight or flight mode and I went for him,” she said.
Sgt Bull, who was a PC at the time, suffered head and neck injuries in the struggle.
She said: “I didn’t think about my own personal safety. I just acted on instinct.” She pinned the gunman to the ground and managed to handcuff him after security officers dashed to the scene of the commotion.
Also PC Stuart Outten was branded Britain’s hardest copper after he Tasered a suspect despite being stabbed with a machete.
He was struck across the head and hand with the foot-long weapon after stopping a van in Leyton, east London, to check the driver’s insurance details.
The officer, 29, brushed aside the accolade and praise.
“I’ve been looking after Londoners for the past 10 years and I’m going back out doing it all again.”
A man has been charged with attempted murder and possessing an offensive weapon.
Meanwhile attacks are contributing to record numbers of police on sick leave for mental health reasons.
More than 10,500 officers took time off work last year suffering from stress, anxiety, depression and post-traumatic stress disorder.
The figure represents a 70% surge over the past five years as the effects of being attacked or witnessing colleagues being beaten or stabbed take their toll.
Police Federation boss John Apter said: “It is not surprising that more and more need to take time away from the frontline.”
