diff --git a/source/java/org/alfresco/repo/domain/QNameDAO.java b/source/java/org/alfresco/repo/domain/QNameDAO.java
index 7e0d25fbde..5f18857890 100644
--- a/source/java/org/alfresco/repo/domain/QNameDAO.java
+++ b/source/java/org/alfresco/repo/domain/QNameDAO.java
@@ -67,6 +67,16 @@ public interface QNameDAO
      */
     NamespaceEntity newNamespaceEntity(String namespaceUri);
     
+    /**
+     * Modifies an existing namespace URI.  If the new URI already exists, then no
+     * new entity is created and a concurrency 
+     * 
+     * @param oldNamespaceUri           the old namespace URI
+     * @param newNamespaceUri           the new namespace URI
+     * @throws AlfrescoRuntimeException if the new namespace is in use
+     */
+    void updateNamespaceEntity(String oldNamespaceUri, String newNamespaceUri);
+    
     /**
      * @param id            the unique ID of the entity
      * @return              the QName entity (never null)
diff --git a/source/java/org/alfresco/repo/domain/QNameDAOTest.java b/source/java/org/alfresco/repo/domain/QNameDAOTest.java
index 275b6c305e..08f8c80ffb 100644
--- a/source/java/org/alfresco/repo/domain/QNameDAOTest.java
+++ b/source/java/org/alfresco/repo/domain/QNameDAOTest.java
@@ -92,6 +92,34 @@ public class QNameDAOTest extends TestCase
         retryingTransactionHelper.doInTransaction(callback);
     }
     
+    public void testRenameNamespace() throws Exception
+    {
+        final String namespaceUriBefore = GUID.generate();
+        final QName qnameBefore = QName.createQName(namespaceUriBefore, "before");
+        final String namespaceUriAfter = GUID.generate();
+        final QName qnameAfter = QName.createQName(namespaceUriAfter, "before");
+        RetryingTransactionCallback<Object> callback = new RetryingTransactionCallback<Object>()
+        {
+            public Object execute() throws Throwable
+            {
+                dao.getOrCreateNamespaceEntity(namespaceUriBefore);
+                // Get a QName that has the URI
+                QNameEntity qnameEntityBefore = dao.getOrCreateQNameEntity(qnameBefore);
+                // Now modify the namespace
+                dao.updateNamespaceEntity(namespaceUriBefore, namespaceUriAfter);
+                // The old qname must be gone
+                assertNull("QName must be gone as the URI was renamed", dao.getQNameEntity(qnameBefore));
+                // The new QName must be present and with the same ID
+                QNameEntity qnameEntityAfter = dao.getQNameEntity(qnameAfter);
+                assertNotNull("Expected QName with new URI to exist.", qnameEntityAfter);
+                assertEquals("QName changed ID unexpectedly.", qnameEntityBefore.getId(), qnameEntityAfter.getId());
+                // Done
+                return null;
+            }
+        };
+        retryingTransactionHelper.doInTransaction(callback);
+    }
+    
     public void testNewQName() throws Exception
     {
         final String namespaceUri = GUID.generate();
diff --git a/source/java/org/alfresco/repo/domain/hibernate/HibernateQNameDAOImpl.java b/source/java/org/alfresco/repo/domain/hibernate/HibernateQNameDAOImpl.java
index b183fe9bd6..380c7c505c 100644
--- a/source/java/org/alfresco/repo/domain/hibernate/HibernateQNameDAOImpl.java
+++ b/source/java/org/alfresco/repo/domain/hibernate/HibernateQNameDAOImpl.java
@@ -116,6 +116,28 @@ public class HibernateQNameDAOImpl extends HibernateDaoSupport implements QNameD
         return namespace;
     }
 
+    public void updateNamespaceEntity(String oldNamespaceUri, String newNamespaceUri)
+    {
+        // First check for clashes
+        if (getNamespaceEntity(newNamespaceUri) != null)
+        {
+            throw new AlfrescoRuntimeException("Namespace URI '" + newNamespaceUri + "' already exists.");
+        }
+        // Get the old one
+        NamespaceEntity oldNamespaceEntity = getNamespaceEntity(oldNamespaceUri);
+        if (oldNamespaceEntity == null)
+        {
+            // Nothing to rename
+            return;
+        }
+        oldNamespaceEntity.setUri(newNamespaceUri);
+        // Flush to force early failure
+        getSession().flush();
+        // Trash the cache
+        qnameEntityCache.clear();
+        // Done
+    }
+
     public QNameEntity getQNameEntity(Long id)
     {
         QNameEntity qnameEntity = (QNameEntity) getSession().get(QNameEntityImpl.class, id);