The proportion of crimes solved by police in England and Wales has fallen to the lowest level recorded, according to Home Office data.
In the 12 months to March, 7.8% of offences saw someone charged or summonsed, down from 9.1% a year ago.
The data began to be compiled in 2015.
It comes after Metropolitan Police Commissioner Cressida Dick acknowledged too many offences were being left unsolved, in a speech about the future of policing.
She said sifting through vast amounts of phone and computer data was partly responsible and called for investment in resources, technology and expertise to drive up clear-up rates.
The Home Office said work to improve crime recording by police forces has "both increased the volume forces are dealing with and changed the crime mix to include more complex cases, such as sexual offences and domestic abuse, which can be more challenging to resolve".
It added: "At the same time, while more crimes are now being recorded, in a growing proportion of cases the victim either doesn't support further action or police are unable to contact them."
Separately, the Office for National Statistics said the Crime Survey for England and Wales - based on people's experience - points to no significant change in overall crime in the year to March, although police recorded offences of robbery rose by 11% and knife crime was up 8%.
It said the increase in this "less frequently occurring but higher-harm types of violence" was consistent with a rising trend in recent years.
The ONS figures show there were 43,516 offences involving a knife or sharp instrument in the 12 months to March - the highest since comparable records began in 2011. The figures exclude Greater Manchester Police which records its data differently.
There were a total of 85,736 offences of robbery, but a 3% fall in burglary.
The total number of killings increased to 701 offences from 693 in the previous 12 months, excluding terror attacks.
The ONS also estimated there were 3.8m fraud offences in the same period, an increase of 17%, but said computer misuse had fallen by about a fifth, driven by a decrease in viruses affecting systems.
Meanwhile, figures show there has been a small increase in the number of police officers in England and Wales over the last year.
As of March 2019 there were 123,171 officers up from 122,405 the previous year. However, there are still 20,500 fewer officers than there were in 2010.
Policing minister Nick Hurd said the chances of being a victim of crime remain low and the government was increasing funding for forces by more than £1bn this year, with the recruitment of more than 3,700 additional officers and staff.
He said: "We are also acting to address the root causes of violence and stop young people being drawn into crime in the first place."
Charlotte Pickles from the think tank Reform said: "Any increases in police numbers must be targeted and coupled with serious investment to tackle the lethal mix of poverty, school exclusion, poor mental health and drugs.
Look-up produced by Wesley Stephenson, Clara Guibourg, Sean Willmott, Becky Rush, Scott Jarvis, and Tom Francis-Winnington