Yes, you can do it, but don't expect the clean taste of a lager. expect more 'character' from the ale yeast and warmer fermentation temperatures.
or, use a lager yeast, and ferment at ale temperatures. See: Steam Beers
Primary: English Mild
On tap: Pale Ale, Lancelot's Wheat, English Brown Ale, Steam Beer, HoovNuts IPA
Bottled: MOAM, Braggot, Raspberry Melomel, Merlot, Apfelwein, Pyment, Sweet mead, Cabernet
Gal in 2009: 27, Gal in 2010: 34, Gal in 2011: 13, Gal in 2012: 10