Slightly different to the usual Ryanair sale, starting tomorrow, prices start at £1 and increase £1 per day to a top sale price of £12 on Dec. 21st.
As usual with Ryanair, limited routes and availability but don't think there are any blackouts on this one. Other info as per their release:
"Ryanair, Europes largest low fares airline, today (9th Dec) began the countdown to Christmas by launching its 12 Days of Christmas - 1 MILLION Seat Sale, which kicks off tomorrow for just 1 euro and increases by 1 euro each day until Sunday 21st December when fares peak at 12 euro one way including taxes.
Ryanairs 12 Days of Christmas Seat Sale fares, which include all taxes and charges, offer seats for travel from 7th January to 12th February on 250 routes across Ryanairs European network."
This will most likely equate to £1-£12 on the UK site but still a good deal IMO if you can get a flight for under £5, otherwise no better than standard Ryanair deals.
*Update 15.18hrs, 09/12/08: Some routes appear to now be on sale at the £1 price. Cannot offer a list of destinations as yet, this will doubtless appear on Ryanair.com later tonight, so it is trial and error to find out, use dates as above (Jan 7- Feb 12).
Thanks to Big Boy for this update!
*Update 15.33hrs, 09/12/08: From Prestwick; Belfast, Bournemouth, Charleroi, Derry, Dublin, Dusseldorf, Frankfurt Hahn, Gothenburg City, Krakow, London Stansted, Oslo Torp, Paris Beauvais, Pisa, Shannon, Stockholm Skavsta, Turin and Wroclaw are ALL showing up with availability at the £1 fare! Better than the usual selection then, remember Ryanair availability for promotions is usually only Mon-Thu and Sat.