Despite pledge to challenge claims, the prosecutions agency is not tracking how many cases it has dropped

The Crown Prosecution Service (CPS) does not know how many rape cases have collapsed after defence claims of “sexsomnia” despite fears the rare medical condition is being exploited.

The prosecutions agency for England and Wales has previously pledged to “robustly challenge” sexsomnia claims after a string of high-profile cases where sexual offence suspects were acquitted – or had their investigations dropped – after the disorder was raised.