They didn't look at a wide range of client devices so other Linux distributions may prove just as secure, as could OSX which seems a notable omission to me considering they included ChromeBooks in the list. It was also pointed out that the disk encryption and VPN solutions haven't been independently verified and they're certainly not CAPS approved; but then again, neither is Microsofts BitLocker solution.
The original page under gov.uk seems to have disappeared (likely as result of all the recent change going on there) but there's a lot on that site which covers end user device security including articles on Ubuntu 12.04 and Windows 7.
However, reading these two articles you don't get the view that Ubuntu is more secure than Windows - in fact, quite the opposite. There's a raft of significant risks associated with Ubuntu (well, seven) whilst only one significant risk is associated with Windows (VPN). Some of the Ubuntu issues look a little odd to me; such as users can ignore cert warnings since this is more a browser issue than OS related unless I've misunderstood as the context isn't very clear, but the basic features are there, just not certified to any significant degree. This is and easy argument for the proprietary solution provides to make and a deal clincher for anyone in government not looking to take risks (most of them). I doubt open-source solutions are really any less secure than these but they do need to get things verified if they're to stand up to these challenges. Governments around the world can have a huge impact on the market and use of open standards and solutions so helping them make the right decisions seems a no-brainer to me. JFDI guys...
Otherwise, the article does have a good list of the sort of requirements to look out for in end-user devices with respect to security which I reproduce here for my own future use:
- Virtual Private Network (VPN)
- Disk Encryption
- Secure Boot
- Platform Integrity and Application Sandboxing
- Application Whitelisting
- Malicious Code Detection and Prevention
- Security Policy Enforcement
- External Interface Protection
- Device Update Policy
- Event Collection for Enterprise Analysis
- Incident Response