The number and proportion of prosecutions dropped at Crown Courts in England and Wales has risen to its highest level in five years.
More than 12,600 cases were discontinued from 2014 to 2015 - one in every eight Crown Court cases.
At the same time, the proportion of Crown Court cases resulting in a conviction fell below the 80% mark for the first time since 2010-11.
The CPS said cases were kept under "constant review".
A study of the data suggested the principal reason for the fall in the proportion of cases resulting in conviction was because of the rise in the number that were dropped by the CPS after charges had been brought.
The total number of cases dropped at that point was 12,615 last year - an increase of nearly 1,700 on the year before.
Pendulum 'swung too far'
BBC home affairs correspondent Danny Shaw said: "In 70% of the dropped prosecutions, the CPS offered 'no evidence'.
"In other words the case was discontinued at a late stage, after the defendant had pleaded not guilty, and often after many months awaiting trial."
He added the figures "are likely to fuel claims that the criminal justice pendulum has swung too far in favour of victims and away from the accused".
A CPS spokesman said: "All cases are kept under constant review as they progress through the criminal justice system.
"If new evidence comes to light, a witness decides to no longer support a prosecution or a co-defendant pleads guilty to the offence, the CPS will then review the case.
"If there is no longer sufficient evidence or if it is no longer in the public interest, the CPS will stop a prosecution."
He added: "In 2014-15 the CPS offered no evidence in 8.8% per cent of cases. This compares to 8.3% the previous year and 9.4% the year before that."
'Cold light of day'
Nazir Afzal, former chief Crown prosecutor of the CPS for north west England, told BBC Radio 4's Today programme: "We have to ensure that we don't have the baying crowd mentality.
"There are lots of people who are desperate for cases to be brought for all sorts of reasons.
"A prosecutor must look at it in the cold light of day, professionally, ensure that they recognise any issues about the credibility of the allegation and make the decision that stands up."
He added: "The accused person needs to have as much information given to him about what happened. That would not necessarily make life any better for him but certainly give an understanding that maybe, just maybe, the decision was right at the outset and something has changed."