IE7, IE8 and Firefox all recognise my <map> but Safari doesn't.

Here's the markup

<img src="corner.jpg" width="96" height="97"
alt="site map" usemap="#sitemap" border="0" />
<map id="sitemap">
<area shape="poly" coords="36,36,80,25,25,80"
href="Garden-shed-story-4.html" alt="Next page" />

I've read a discussion about how Safari seems to take longer to load it but I'm not getting anywhere with that.

Any ideas please?