diff --git a/src/ORM/DataObject.php b/src/ORM/DataObject.php
index 94f726a71be..bc293979f5c 100644
--- a/src/ORM/DataObject.php
+++ b/src/ORM/DataObject.php
@@ -3633,7 +3633,6 @@ public function requireTable()
         $fields = $schema->databaseFields(static::class, false);
         $indexes = $schema->databaseIndexes(static::class, false);
         $extensions = self::database_extensions(static::class);
-        $legacyTables = $schema->getLegacyTableNames(static::class);
 
         if (empty($table)) {
             throw new LogicException(
@@ -3641,26 +3640,6 @@ public function requireTable()
             );
         }
 
-        if ($legacyTables) {
-            $ignore = Config::inst()->get(static::class, 'ignored_legacy_tables') ?: [];
-            $renameTables = array_diff(
-                array_intersect($legacyTables, DB::table_list()),
-                $ignore
-            );
-            if (count($renameTables) > 1) {
-                $class = static::class;
-                $legacyList = implode(', ', $renameTables);
-                trigger_error(
-                    "Class $class has multiple legacy tables: $legacyList",
-                    E_USER_NOTICE
-                );
-            }
-            if (count($renameTables) === 1) {
-                $dbSchema = DB::get_schema();
-                $dbSchema->renameTable($renameTables[0], $table);
-            }
-        }
-
         if ($fields) {
             $hasAutoIncPK = get_parent_class($this ?? '') === self::class;
             DB::require_table(
diff --git a/src/ORM/DataObjectSchema.php b/src/ORM/DataObjectSchema.php
index 71aaaa430d1..dcd7ca17d7a 100644
--- a/src/ORM/DataObjectSchema.php
+++ b/src/ORM/DataObjectSchema.php
@@ -318,30 +318,18 @@ protected function buildTableName($class)
     {
         $table = Config::inst()->get($class, 'table_name', Config::UNINHERITED);
 
-        // Return table name if configured
+        // Generate default table name
         if ($table) {
             return $table;
         }
 
-        // Use classname directly if not namespaced
         if (strpos($class ?? '', '\\') === false) {
             return $class;
         }
 
-        // Attempt to generate a nice table name
-        $separator = DataObjectSchema::config()->uninherited('table_namespace_separator') ?? '';
-        $parts = explode('\\', trim($class ?? '', '\\'));
-        $vendor = array_slice($parts, 0, 1)[0];
-        $base = array_slice($parts, -1, 1)[0];
-        if ($vendor && $base && $vendor !== $base) {
-            $table = "{$vendor}{$separator}{$base}";
-        } elseif ($base) {
-            $table = $base;
-        } else {
-            throw new InvalidArgumentException("Unable to build a table name for class '$class'. Define a table_name for this class.");
-        }
+        $separator = DataObjectSchema::config()->uninherited('table_namespace_separator');
+        $table = str_replace('\\', $separator ?? '', trim($class ?? '', '\\'));
 
-        // Display a warning about namespaced classes producing long table names
         if (!ClassInfo::classImplements($class, TestOnly::class) && $this->classHasTable($class)) {
             DBSchemaManager::showTableNameWarning($table, $class);
         }
@@ -349,18 +337,6 @@ protected function buildTableName($class)
         return $table;
     }
 
-    /**
-     * @param $class
-     * @return array
-     */
-    public function getLegacyTableNames($class)
-    {
-        $separator = DataObjectSchema::config()->uninherited('table_namespace_separator');
-        $names[] = str_replace('\\', $separator, trim($class, '\\'));
-
-        return $names;
-    }
-
     /**
      * Return the complete map of fields to specification on this object, including fixed_fields.
      * "ID" will be included on every table.
diff --git a/tests/php/ORM/DataObjectSchemaTest.php b/tests/php/ORM/DataObjectSchemaTest.php
index 455b8461abc..8c18660eb23 100644
--- a/tests/php/ORM/DataObjectSchemaTest.php
+++ b/tests/php/ORM/DataObjectSchemaTest.php
@@ -58,9 +58,9 @@ public function testTableName()
             'DOSTWithCustomTable',
             $schema->tableName(WithCustomTable::class)
         );
-        // Default table name is Vendor plus base class
+        // Default table name is FQN
         $this->assertEquals(
-            'SilverStripe_DefaultTableName',
+            'SilverStripe_ORM_Tests_DataObjectSchemaTest_DefaultTableName',
             $schema->tableName(DefaultTableName::class)
         );
     }