The link in this picture, of course, doesn't go to the IRS's website. Instead, it links to a bare IP address. Our friends in the UK aren't being left out, either:
The link in this phish went to a page at a free webhosting provider, not to the HMRC website.
There are many steps you can take to protect yourself. Make sure you've got the latest version of your web browser, as most have added functionality to point out suspicious sites. You can also install a third-party toolbar (like the Netcraft Anti-Phishing toolbar) that warns you of suspicious sites. Most importantly, be alert - know the web addresses of your revenue service (http://www.irs.gov for the US, http://www.hmrc.gov.uk for the United Kingdom) and your bank(s), and don't enter personal information on a website unless you're positive you're on the correct site. If you have a question about the legitimacy of a site, you can call the customer support line of your bank or your revenue service to confirm.