I would not float the main content, but rather have it be a normal block with the left column floated left within it, something like this:
<!DOCTYPE HTML PUBLIC "-//W3C//DTD HTML 4.01//EN"
"http://www.w3.org/TR/html4/strict.dtd">
<html lang='en'>
<head>
<meta http-equiv='Content-Type' content=
'text/html; charset=us-ascii'>
<title>
Untitled
</title>
<style type="text/css">
<!--
body {
margin: 0;
padding: 0;
background-color: navy;
}
#container {
margin: 0 10% 5px;
padding: 10px 10px 10px 165px;
background: white url(http://v2.btronics.co.uk/images/main_frame_bg.jpg)
repeat-y 0 0;
color: black;
border: solid 3px black;
border-top: none;
}
#head {
margin: 5px 10% 0;
padding: 10px;
background: navy url(http://v2.btronics.co.uk/images/header2.jpg) repeat 0 50%;
color: white;
border: solid 3px black;
border-bottom solid 1px black;
}
#left {
float: left;
margin: 0 0 0 -175px;
padding: 5px
}
.clear {
height: 1px;
clear: both;
font-size: 1px;
line-height: 1px;
}
-->
</style>
</head>
<body>
<h1 id="head">
Test Page
</h1>
<div id="container">
<div id="left">
<ul>
<li>This is...
</li>
<li>...the left...
</li>
<li>...column
</li>
</ul>
</div>
<h2>
Main Section
</h2>
<p>
Lorem ipsum dolor sit amet, consectetur adipisicing elit,
sed do eiusmod tempor incididunt ut labore et dolore
magna aliqua. Ut enim ad minim veniam, quis nostrud
exercitation ullamco laboris nisi ut aliquip ex ea
commodo consequat. Duis aute irure dolor in reprehenderit
in voluptate velit esse cillum dolore eu fugiat nulla
pariatur.
</p>
<p>
Excepteur sint occaecat cupidatat non proident, sunt in
culpa qui officia deserunt mollit anim id est laborum.
Lorem ipsum dolor sit amet, consectetur adipisicing elit,
sed do eiusmod tempor incididunt ut labore et dolore
magna aliqua. Ut enim ad minim veniam, quis nostrud
exercitation ullamco laboris nisi ut aliquip ex ea
commodo consequat.
</p>
<h3>
H3 Heading
</h3>
<p>
Duis aute irure dolor in reprehenderit in voluptate velit
esse cillum dolore eu fugiat nulla pariatur. Excepteur
sint occaecat cupidatat non proident, sunt in culpa qui
officia deserunt mollit anim id est laborum. Lorem ipsum
dolor sit amet, consectetur adipisicing elit, sed do
eiusmod tempor incididunt ut labore et dolore magna
aliqua.
</p>
<p>
Lorem ipsum dolor sit amet, consectetur adipisicing elit,
sed do eiusmod tempor incididunt ut labore et dolore
magna aliqua. Ut enim ad minim veniam, quis nostrud
exercitation ullamco laboris nisi ut aliquip ex ea
commodo consequat. Duis aute irure dolor in reprehenderit
in voluptate velit esse cillum dolore eu fugiat nulla
pariatur.
</p>
<div class="clear"></div>
</div>
</body>
</html>
