In this appeal from a violation of probation proceeding, appellant timely raised the issue of a Richardson v. State, 246 So.2d 771 (Fla. 1971), violation with respect to the state’s most important witness. A Richardson hearing is required in a probation revocation proceeding. See Cuciak v. State, 410 So.2d 916 (Fla. 1982). The circuit court did not conduct a Richardson inquiry. The state has failed to demonstrate that the failure to conduct such a hearing was harmless. The state’s witness had been drinking and using cocaine on the night in question, but said that she was not “obliviated.” Although defense counsel had 30 minutes to interview the witness prior to the hearing, proper notice of the witness would have given the defense time to more fully develop an effective impeachment strategy.

Reversed and remanded.