Crime figures are likely to rise significantly if tough checks are brought in on how the police record them, according to the head of the statistics watchdog.
Sir Andrew Dilnot expressed regret that his UK Statistics Authority (UKSA) had not highlighted major problems with the information earlier.
He insisted it is crucial that proper auditing procedures are introduced to check information is accurate and not being manipulated.
Sir Andrew issued the warning as he gave evidence to MPs after the UKSA withdrew its "gold standard" mark from police crime figures.
The move last week means the data for England and Wales, published by the Office for National Statistics (ONS), effectively come with a health warning.
Sir Andrew told the Public Administration Committee: "If, through the introduction of a rigorous auditing process, we see anything like what we saw when that first happened some decade or so ago, it is quite conceivable that the police-recorded crime data could show an increase in the number of crimes recorded over the next little while...
"It is quite conceivable, indeed I think quite likely, that if there is proper auditing introduced, the recording of crime is improved, that we will see recorded crime increase."
Sir Andrew said there had been inadequate auditing of police crime figures since 2007-8, and statisticians had been voicing concerns about that for several years.
Those doubts had been heightened by the gap between the police data and the Crime Survey for England and Wales - which is still regarded as solid by UKSA.
But Sir Andrew admitted that a formal review of the statistics had not been launched until last June.
"Do I wish that we had been even swifter than that?" he said. "The answer is, honestly, yes. Given the concerns that we had repeatedly expressed about the lack of adequate audit and lack of progress on periodic and regular audit in the last three years, it would have, in my view, been good to have got to where we got to more quickly than we did."
John Flatley, head of crime statistics at the ONS, said some police officers appeared to be "confused" about whether offences should be recorded if there was not enough evidence to bring a charge.