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:
1978 Berwick and East Lothian by-election
Table title:
Votes
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 > Labour </td><td class="highlighted"  colspan=1 rowspan=1 > John Home Robertson </td><td colspan=1 rowspan=1 > 20,530 </td><td colspan=1 rowspan=1 > 47.4 </td><td colspan=1 rowspan=1 > +4.1 </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > Conservative </td><td colspan=1 rowspan=1 > Margaret Marshall </td><td colspan=1 rowspan=1 > 17,418 </td><td colspan=1 rowspan=1 > 40.2 </td><td colspan=1 rowspan=1 > +2.6 </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > SNP </td><td colspan=1 rowspan=1 > Isobel Lindsay </td><td colspan=1 rowspan=1 > 3,799 </td><td colspan=1 rowspan=1 > 8.8 </td><td colspan=1 rowspan=1 > −4.4 </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 > Liberal </td><td colspan=1 rowspan=1 > Tam Glen </td><td colspan=1 rowspan=1 > 1,543 </td><td colspan=1 rowspan=1 > 3.6 </td><td colspan=1 rowspan=1 > −2.3 </td></tr>
<tr> <th colspan=3 rowspan=1 > Majority </th><td class="highlighted"  colspan=1 rowspan=1 > 3,112 </td><td colspan=1 rowspan=1 > 7.2 </td><td colspan=1 rowspan=1 > +1.5 </td></tr>
<tr> <th colspan=3 rowspan=1 > Turnout </th><td colspan=1 rowspan=1 > 43,290 </td><td colspan=1 rowspan=1 >  </td><td colspan=1 rowspan=1 >  </td></tr>
<tr> <td colspan=1 rowspan=1 >  </td><td colspan=2 rowspan=1 > Labour hold </td><th colspan=1 rowspan=1 > Swing </th><td colspan=1 rowspan=1 > +0.8 </td><td colspan=1 rowspan=1 >  </td></tr>
</table>
Question:
how many votes did Home Robertson win with ?
Answer:
The result was a victory for Home Robertson, with majority of 3,112 votes.