A police officer is assaulted every 24 minutes - 60 a day across the UK, a Jane's Police Review survey suggests.
One out of every three forces recorded a fall in assaults
There were 21,845 assaults on officers in 51 police forces across England, Wales, Scotland and Northern Ireland in the year 2004-5, it concludes.
Among the 49 forces which provided data last year there were was a rise of 547 assaults year-on-year.
The Police Federation's health and safety committee secretary, Paul Lewis, called the figures "horrendous".
Police Review editor Catriona Marchant called them "shockingly high".
"Courts need to deal severely with offenders who assault officers, and send out a strong message that attacking a police officer will not be tolerated by society," she added.
"What the service must ensure is excellent officer safety training and annual refreshers that lead to confident, well-trained officers who, with the right equipment, will reduce the risk of attack."
Officers wanted people to know the job was dangerous, Ms Marchant told BBC Radio 4's Today programme.
"Very few people wake up and think they are going to be... physically abused," she added.
Avon and Somerset constabulary reported the biggest year-on-year increase - from 534 to 728.
But one out of every three forces recorded a fall in assaults on officers.
The safest in England and Wales was Northamptonshire, where there were just 90 assaults in the year.
Assaults on Scottish officers fell by 158 to 1,092.
Strathclyde accounted for 479 half of these, although that force's total was down 108 year-on-year.
In the Police Service of Northern Ireland, the figure rose 152 to 2,214.