Nope. The GPS unfortunately requires a network connection to get it's initial fix, for whatever reason. Therefore, you'll be out of luck in England with the Droid.
Incorrect responses above. The GPS receiver will be just fine. GPS relies on the network of GPS satellites to determine your location.
You say "navigation" but that's extremely vague and you need to be specific about which nav app you're using. Google Maps Nav (which is entirely separate from the GPS receiver -- just like any other GPS-enabled app) requires data. If you have a GPS nav app that uses local map data you'll be fine. Be aware though that the Droid's radio apparently needs to be on (actual coverage doesn't matter) to get an initial fix.