Please read the following table in HTML format from a webpage and then answer the question in detail according to the table. Each table cell is defined by a <td> and a </td> tag. Each table row starts with a <tr> and ends with a </tr> tag. 'rowspan=m' and 'colspan=n' represents a cell spaning over 'm' rows and 'n' columns.

Webpage title:
Birkenhead (UK Parliament constituency)
Table title:
MPs since 1950
Table:
<table id='hittask' contenteditable='False'>
<tr> <th colspan=2 rowspan=1 > Election </th><th colspan=1 rowspan=1 > Member </th><th colspan=1 rowspan=1 > Party </th></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > 1950 </td><td colspan=1 rowspan=1 > Percy Collick </td><td colspan=1 rowspan=1 > Labour </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > 1964 </td><td colspan=1 rowspan=1 > Edmund Dell </td><td colspan=1 rowspan=1 > Labour </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td class="highlighted"  colspan=1 rowspan=1 > 1979 </td><td class="highlighted"  colspan=1 rowspan=2 > Frank Field </td><td class="highlighted"  colspan=1 rowspan=1 > Labour </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td class="highlighted"  colspan=1 rowspan=1 > 2018 </td><td class="highlighted"  colspan=1 rowspan=1 > Independent </td></tr>
</table>
Question:
Who has represented the Birkenhead constituency since 1979 and what party was he apart of until 2018?
Answer:
Birkenhead is a constituency of the UK Parliament since 1979 represented by Frank Field, who sits as an independent MP, having previously been a member of the Parliamentary Labour Party until 2018.