Apparently the English wine industry is flourishing with land under cultivation up by 45% in the past four years.
Most English Grapes end up in sparkling wine, it is expected that within the next 8 years there could be 5 million bottles a year produced (as a guide France produces 50 million).
The additional vines have been planted by two of the biggest producers, Chapel Down (who I've heard of) and Nyetimber (who I haven't, they are in Sussex!). Also Waitrose has started planting chardonnay, pinot noir and pinot meunier grapes at its Leckford Estate in Hampshire.
Getting hold of English Wines is difficult, your best bet is Waitrose. They tend to stock some of the Chapel Down wines (Bachuus, Flint Dry) and they will often stock a local wine.
If you want to try English wine it may be worth checking out this list of English and Welsh vinyards. This list is not complete and I know of two vinyards not on the list. The vinyard may have a list of outlets or have a shop. The English Wine Centre near Alfriston in Sussex has a good range (but they are pricey - I'm sure they charge more for Chapel Down than Waitrose, but then Waitrose probably get a bigger discount!). National Trust shops also sell English wine - Ickworth sells its own wine (which is excellent), Stourhead sells Bow in the Clouds and Lanhydrock sells Camel.
I've drunk, and thoroughly enjoyed wine, from a number of different vinyards included Chapel Down (Kent), Camel (Cornwall), Denbies (Surrey), Sandyford Vinyard (Essex) and Bow in the Clouds (Wiltshire). If you enjoy a glass it'll make a nice change from your typical French, Australian, South African and Californian. You'll be surprised how good it is as well.