I did a quick search and realised that my site had fallen victim to a version of the WordPress Pharma Hack – a particularly sneaky hack which means everybody apart from Google sees the normal version of your page, meaning that you can be blissfully unaware that you’ve been hacked until you see something odd in your search results. To solve the problem, you need to see your site as Google sees it. The most accurate way of doing this is to use Google Webmaster Tools. When you log in, under Diagnostics you can go to “Fetch as Googlebot”. I entered the page and waited a few seconds for Google to fetch it, then by clicking the “Success” link I was able to see the HTML that Google was seeing: