Some 80 robberies a day were closed last year without a suspect being identified, the Liberal Democrats have claimed.
The party said it had commissioned research showing 30,000 muggings went unsolved in 2022 across England and Wales.
It accused Home Secretary Suella Braverman of becoming “embroiled in endless scandals” while violent criminals are “let off the hook”.
The House of Commons Library research shows that more than one in two robbery reports (54%) went unsolved, the Lib Dems said.
Fewer than one in 12 (8%) led to a suspect being charged, according to the party.
These shocking figures show muggings are being effectively decriminalised, with far too many violent criminals let off the hook— Lib Dem Treasury spokeswoman Sarah Olney
The figures include cases of robbery of personal property which involve violence or threats to the victim.
West Midlands Police was the worst performing force, with just 4% of robberies reported in 2022 leading to a suspect being charged, the Lib Dems said.
It was closely followed by Northamptonshire (5%), Avon and Somerset (6%) and Hampshire (6%), according to the research.
Lib Dem Treasury spokeswoman Sarah Olney MP, who commissioned the research, said: “These shocking figures show muggings are being effectively decriminalised, with far too many violent criminals let off the hook.
“People are being left feeling unsafe walking down their own local streets, because this Conservative Government has slashed neighbourhood policing to the bone.
“Crime victims are being abandoned while the Home Secretary Suella Braverman is embroiled in endless scandals.”
Ms Braverman was cleared without an independent investigation by Prime Minister Rishi Sunak last week over allegations she broke the ministerial code.
She was found to have breached the code last year over the sending of an official document from a personal email account.
Mr Sunak has said he did not let the Home Secretary, an influential figure on the right of the party, “off the hook”, after she asked officials if she could attend a private speed awareness course following a speeding offence.
The Lib Dems and Labour have both called for a return to “community policing” with a focus on officers who know the neighbourhood well.
The Government has said it has policing under control, with recent figures showing that it met its manifesto pledge to recruit 20,000 new officers by March 2023.
A Home Office spokesman said: “Robbery is an invasive and unsettling crime for victims and we expect police to take all incidents seriously.
“We are providing police with the resources they need, having delivered on our commitment to recruit 20,000 additional police officers by March 2023, the highest it has ever been.
“We are also supporting police by providing funding for crime prevention measures, including better street lighting and CCTV, and equipping police with better technology to help their investigations and catch more criminals.”
A Conservative spokesman said: “The Liberal Democrats are once again proving themselves to be the very best hypocrites in British politics.
“If they really cared about cracking down on crime, they would have backed our legislation that gives the police the powers they need to clamp down on criminals.
“The Conservatives have recruited over 20,000 more police officers since 2019, and we are ensuring they have the tools they need to see justice delivered and victims protected.”
