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:
1921 Lewisham West by-election
Table title:
Result
Table:
<table id='hittask' contenteditable='False'>
<tr> <th colspan=2 rowspan=1 > Party </th><th colspan=1 rowspan=1 > Candidate </th><th colspan=1 rowspan=1 > Votes </th><th colspan=1 rowspan=1 > % </th><th colspan=1 rowspan=1 > ± </th></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > Unionist </td><td class="highlighted"  colspan=1 rowspan=1 > Philip Dawson </td><td colspan=1 rowspan=1 > 9,427 </td><td colspan=1 rowspan=1 > 38.9 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > Anti-Waste League </td><td colspan=1 rowspan=1 > Walter George Windham </td><td colspan=1 rowspan=1 > 8,580 </td><td colspan=1 rowspan=1 > 35.4 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > Liberal </td><td colspan=1 rowspan=1 > Frank Raffety </td><td colspan=1 rowspan=1 > 6,211 </td><td colspan=1 rowspan=1 > 25.6 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <th colspan=3 rowspan=1 > Majority </th><td class="highlighted"  colspan=1 rowspan=1 > 847 </td><td colspan=1 rowspan=1 > 3.5 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <th colspan=3 rowspan=1 > Turnout </th><td colspan=1 rowspan=1 > 24,218 </td><td colspan=1 rowspan=1 > 59.2 </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=2 rowspan=1 > Unionist hold </td><th colspan=1 rowspan=1 > Swing </th><td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 >  </td></tr>
</table>
Question:
Who won the 1921 Lewisham West by-election, and what was the majority margin of victory?
Answer:
Dawson was elected with a majority of 847.