This is happening again. For bookings between 23rd and 29th November, for travel between 10 December and 22 January 2011. Available online and from station booking offices. Cheapest single fares range from £17 for a London/West Midlands journey to £40 for a London/Glasgow journey. Worth checking out - full details are on the "Travel Trade" page of Virgin's website. Apologies if someone beat me to it, but I didn't find the post if so!