Police should refer to people who report rape as complainants rather than victims, senior legal figures said last night, amid warnings that the policy is undermining impartiality and leading to miscarriages of justice.

MPs and members of the judiciary have also called for an overhaul of the current guidelines which demand that officers automatically believe complainants from the outset.

Scotland Yard has ordered an urgent review of scores of sex abuse cases, including 30 which are about to go to trial, after it emerged that crucial material had been withheld from defence lawyers.

Two rape cases collapsed in the last week, because a detective constable in the Met's Child Abuse and Sexual Offences (CASO) unit, failed to disclose texts messages undermining the complainants' stories.

It raises concerns that dozens more cases could be thrown out by the courts and could potentially spark a raft of appeals by convicted rapists.

While the officer involved, Detective Constable Mark Azariah, has been removed from active duties, lawyers said the problem was not down to one rogue officer, but systemic problems caused by the current approach to sex abuse cases.