Nested xsl for-each

Don't know why this code doesn't work. It will work when the loops aren't nested.
ANy help would be great!!

            
            
            <xsl:for-each select="QUERY_RESULTS/POLICY">
                  
                  <tr>
                  <td><b>Policy Number: </b></td>
                  <td><font color="blue"><xsl:value-of select="policy_number" /></font></td>
                  </tr>

                  <xsl:for-each select="QUERY_RESULTS/POLICY/VRM_DETAILS">
                        <tr>
                        <td><font color="blue"><xsl:value-of select="effective_date" /></font></td>
                        <td><font color="blue"><xsl:value-of select="expiry_date" /></font></td>
                        </tr>
                  </xsl:for-each>


                  </xsl:for-each>