By Alex Stevenson
Nearly 5,000 extra sexual offences would be detected each year if police improved their clear-up rate to those of the best five forces, according to the Liberal Democrats.
Based on crime figures from England and Wales in 2007/08, the Lib Dems worked out how many extra crimes would be uncovered if detection rates were increased to the national average and then increased to the minimum level of the top five police forces.
They found 416,461 extra crimes would be detected overall, including over 130,000 violent offences and 50,000 robberies and burglaries.
And they claimed over 80,000 crimes would be solved that are not today as a result, including nearly 35,000 violent crimes and almost 900 sexual offences.
"We can cut crime by spreading best practice from the top police forces," Lib Dem home affairs spokesperson Chris Huhne said.
"Catching more criminals means more police on the street for longer, intensive policing in hotspots and learning from what works."
Mr Huhne said policing and criminal justice policy had been distracted by Britain's' two main parties sounding tough rather than taking effective action.
"You could introduce sharia law in Britain and it would make little difference unless detection rates improve," he added.
"The best police forces can show the way."