I worked on the HMRC desktop upgrade project in 2006 (NT4 -> XP). I worked for the testing teams who had the mommoth task of validating the XP platform for everything that was currently being done on NT4.

Do you have *any* idea the amount of apps that dept (HMRC) alone used?? Yeah there were the bog standard office apps, but then there were customised apps based on those (Excel, Access, etc), Outlook for the Exchange backend, and then there were HUNDREDS of other apps used for more specific tasks. Add in legacy apps, access to mainframe services, old but critical odds and sods... the bottom line is that just moving all of that onto Linux would probably take years. And some of it would probably never make it, so you'd need to either source or develop alternatives, or some kind of Citrix/virtualised solution.

And as to the muppet who seems to think "civil servants" just type numbers into a green screen or something and so only need a cut down desktop, well it might surprise you to realise the majority of them are just like any other 21st century corporate worker, with all the same requirements on the desktop/laptop. And ALL the same issues. Note that I bet pretty much all govt depts outsource (at least) their desktop infrastructure to the big services companies - why? 'Cos at the end of the day they have pretty much the same stuff as every other big business.

I'm not saying there aren't savings to be found, but rip-and-replace with OSS is not the simple answer.