In a post on the (then) Alphagov blog in April last year about design principles:
Given it has 3.5% UK market share and Microsoft are trying to persuade everyone to shift off it, we assumed IE6 is dead (actually, we were a tad ruder than that).
The blog post was illustrated by a photograph showing design principles scribbled on cards, and stuck around the room (which was in the old COI headquarters of Hercules House). See that 'IE6' one disappearing off the top? There's a very good reason why the photo is cropped precisely there. Clue: four letters, begins with F.
I think this is a well-intentioned mistake. Gov.uk is a clean slate, a rare opportunity to force people to upgrade, for their own good. GDS is a future-oriented operation, charged with leading a revolution in the delivery of public services. Oh - and cutting costs, too. Ask any web developer about the cost, in terms of both person hours and opportunity cost, of supporting IE6.
This effective endorsement of the continued use of an 11 year old browser is entirely contradictory to that mission. Sure, they'd take some flak for it. But it would be an opportunity to promote the message of 'Government’s preferred online security advice channel', GetSafeOnline, which states quite categorically: 'Always ensure that you are running the latest version of your chosen browser.'