Defendants in money laundering conspiracy trials must know the cash involved is ill-gotten in order to be convicted, an Appeal Court has ruled.
The Appeal Court case followed a Law Lords ruling last year
The court upped the burden of proof as it quashed the convictions of four men jailed for conspiracy to launder hundreds of millions of pounds.
It said alleged conspirators must know - not just suspect - the money is the proceeds of crime, to be found guilty.
The prosecution said the decision would have a "wide knock-on effect".
Lord Justice Hopper, sitting with Mr Justice Tugendhat and Sir Douglas Brown, said: "The money must be proved to have been the proceeds of drug trafficking or other criminal conduct."
The court certified the case raised a point of law of general public importance - allowing prosecutors to appeal to the House of Lords.
Crown prosecutor Martin Bethel QC told the judges their decision would effect other conspiracy cases, including those involving the handling of stolen property.
Last year, Law Lords ruled that laundered money must be proved to have come from crime before a defendant could be convicted of the offence of money laundering.
In June 2003, Liaquat Ali, Akhtar Hussain and Moshan Khan were convicted of conspiracy to conceal, disguise or remove from the jurisdiction £170 million proceeds of drug trafficking.
It was alleged the money was laundered through a legitimate travel agency and money transfer company, Watan Travel, based in Bradford and Birmingham.
Leeds Crown Court sentenced Mr Ali and Mr Hussain to 12 years in prison and Mr Khan to eight years.
In October 2004, the same court sentenced Shahid Bhatti to six years for a similar conspiracy relating to the Bradford Travel and Bradford Currency Exchange.
All four men denied knowing or suspecting that some of the money they handled was the proceeds of crime.
On Tuesday, the Appeal Court said if the Crown appealed to the Lords and lost, Mr Ali, Mr Hussain and Mr Khan should face a retrial on conspiracy charges.
The reference to their having "reasonable grounds to suspect" that the money came from crime should be omitted in that instance, it said.
No decision was made on whether Mr Bhatti should face a retrial.
The court set conditions for the defendants' release on bail pending the further hearings.