That is according to a leaked Home Office document prepared as part of a new Government strategy to tackle the increase in crime.
The paper said criminals may have been “encouraged” by the reduction in police staffing numbers and a fall in prosecution rates.
It comes after ministers, including Home Secretary Amber Rudd, denied that the decline in the number of police officers was a reason for the rise in violent crime.
The paper, Serious Violence; Latest Evidence On The Drivers, which was obtained by The Guardian, said: “Since 2012/3, weighted crime demand on the police has risen, largely due to growth in recorded sex offences.
“At the same time officers’ numbers have fallen by 5% since 2014.
“So resources dedicated to serious violence have come under pressure and charge rates have dropped.
“This may have encouraged offenders.”
#TSG#U225 just arrested a Male who had earlier threatened a member of the public with this Samurai sword @MPSSouthwark A controlled #Taser callout was the tactic utilised to https://t.co/b5Uw1Cttdt injuries.#Knifecrime Any Q’s? Let’s go! #retweetpic.twitter.com/OO4e5TNKRO
— MetTaskforce (@MetTaskforce) April 8, 2018
It was “unlikely to be the factor that triggered the shift in serious violence, but may be an underlying driver that has allowed the rise to continue”.
A highlighted box summarised the point: “Not the main driver but has likely contributed.”
Between the end of March 2010 and 2017, the number of police officers in the UK’s 43 forces fell from 143,734 to 123,142.
Since the beginning of this year more than 50 people have died in London as a result of crime.
Commenting on that figure, Ms Rudd had said in The Sunday Telegraph: “In the early Noughties, when serious violent crimes were at their highest, police numbers were rising.
“In 2008, when knife crime was far greater than the lows we saw in 2013-14, police numbers were close to the highest we’d seen in decades.
“So while I understand that police are facing emerging threats and new pressures – leading us to increase total investment in policing – the evidence does not bear out claims that resources are to blame for rising violence. “
Policing Minister Nick Hurd had told the BBC that the system was “stretched” but insisted it was “categorically not the case” that a cut in officer numbers was behind the rise in violent crime.
Communities Secretary Sajid Javid had also told the BBC’s Andrew Marr Show: “For anyone to suggest that this is caused by police numbers, it is not backed up by the facts.”
Shadow home secretary Diane Abbott said: “If true, this blows apart the Tories’ repeated claims that their cuts have had no effect.
“Cuts reduce police effectiveness and their ability to apprehend criminals. It also undermines the reassurance and deterrent effect that a police presence can have.
“If the Government’s own serious violence strategy accepts that police cuts have had an effect, why can’t the Government itself?”
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Labour leader Jeremy Corbyn and London Mayor Sadiq Khan will launch the party’s local election campaign later.
The Home Office said it would not comment on a leaked document.