diff --git a/libs/prison-staff/src/main/kotlin/uk/gov/justice/digital/hmpps/repository/PrisonStaffRepository.kt b/libs/prison-staff/src/main/kotlin/uk/gov/justice/digital/hmpps/repository/PrisonStaffRepository.kt
index 54ed1d971..2630e49d6 100644
--- a/libs/prison-staff/src/main/kotlin/uk/gov/justice/digital/hmpps/repository/PrisonStaffRepository.kt
+++ b/libs/prison-staff/src/main/kotlin/uk/gov/justice/digital/hmpps/repository/PrisonStaffRepository.kt
@@ -15,7 +15,10 @@ interface PrisonStaffRepository : JpaRepository<PrisonStaff, Long> {
     @Query(
         """
         select officer_code from staff
-        where regexp_like(officer_code, ?1, 'i')
+        where officer_code like :regex || '%'
+        and substr(officer_code,5,1) in ('0','1','2','3','4','5','6','7','8','9')
+        and substr(officer_code,6,1) in ('0','1','2','3','4','5','6','7','8','9')
+        and substr(officer_code,7,1) in ('0','1','2','3','4','5','6','7','8','9')
         order by officer_code desc
         fetch next 1 rows only
         """,
diff --git a/libs/prison-staff/src/main/kotlin/uk/gov/justice/digital/hmpps/service/OfficerCodeGenerator.kt b/libs/prison-staff/src/main/kotlin/uk/gov/justice/digital/hmpps/service/OfficerCodeGenerator.kt
index 8706bd82a..247e61558 100644
--- a/libs/prison-staff/src/main/kotlin/uk/gov/justice/digital/hmpps/service/OfficerCodeGenerator.kt
+++ b/libs/prison-staff/src/main/kotlin/uk/gov/justice/digital/hmpps/service/OfficerCodeGenerator.kt
@@ -13,7 +13,7 @@ class OfficerCodeGenerator(private val staffRepository: PrisonStaffRepository) {
             throw StaffCodeExhaustedException(probationAreaCode)
         }
         val prefix = probationAreaCode.substring(0, 3) + alphabet[index]
-        val latest = staffRepository.getLatestStaffReference("^$prefix\\d{3}$")
+        val latest = staffRepository.getLatestStaffReference(prefix)
         val number = latest?.substring(latest.length - 3)?.toInt()?.plus(1) ?: 1
         return if (number > 999) {
             generateFor(probationAreaCode, index + 1)
diff --git a/libs/prison-staff/src/test/kotlin/uk/gov/justice/digital/hmpps/service/OfficerCodeGeneratorTest.kt b/libs/prison-staff/src/test/kotlin/uk/gov/justice/digital/hmpps/service/OfficerCodeGeneratorTest.kt
index e89d1014a..b92995178 100644
--- a/libs/prison-staff/src/test/kotlin/uk/gov/justice/digital/hmpps/service/OfficerCodeGeneratorTest.kt
+++ b/libs/prison-staff/src/test/kotlin/uk/gov/justice/digital/hmpps/service/OfficerCodeGeneratorTest.kt
@@ -29,8 +29,7 @@ class OfficerCodeGeneratorTest {
     fun `if all possible options exhausted exception thrown`() {
         whenever(staffRepository.getLatestStaffReference(anyString()))
             .thenAnswer {
-                val regex = it.arguments[0] as String
-                val prefix = regex.substring(1, regex.length - 6)
+                val prefix = it.arguments[0] as String
                 prefix + "999"
             }
 
@@ -54,8 +53,7 @@ class OfficerCodeGeneratorTest {
     fun `roll over to next letter is successful`() {
         whenever(staffRepository.getLatestStaffReference(anyString()))
             .thenAnswer {
-                val regex = it.arguments[0] as String
-                val prefix = regex.substring(1, regex.length - 6)
+                val prefix = it.arguments[0] as String
                 if (prefix == "${probationAreaCode}A") {
                     prefix + "999"
                 } else {