This is the most detailed and recent study, where they went through all rape cases in the UK with a fine comb. It puts the most likely figure of false accusations at 3%, within a range of 1% to 9%.

Other numbers:

- 7% (of all women) had been raped,

- Around 75% of those cases were reported to police

- only 14% of cases resulted in a trial

- less than half of trials resulted in conviction

- Police officers guess that 30% of reported rapes are false accusations when asked in general terms, even though these same officers came to such a conclusion in only 9% of specific cases they handled.

http://webarchive.nationalarchives.gov.uk/20110218141141/htt...