<page_title> List of Hertfordshire boundary changes </page_title> <section_title> List of changes </section_title> <table> <cell> 1 April 1965 <col_header> Date </col_header> </cell> <cell> London Government Act 1963 <col_header> Legislation </col_header> </cell> <cell> Potters Bar Urban District gained from Middlesex Former area of Barnet Urban District and East Barnet Urban District transferred to Greater London <col_header> Effect </col_header> </cell> </table>
In 1965, the Middlesex former area was transferred to Greater London under the London Government Act 1963.