After losing ALL my tomato crops to blight for the past 5 years I was finally about to give up... then Gardeners World mentioned a variety last evening that is supposedly blightproof.
Only found one UK supplier, and at 95p for 30 seeds I think they're worth a try.
http://www.packetseeds.com/acatalog/...-_Koralik.html
After trying other "blight resistant" varieties at great expense, this variety might at least be an answer............