Up until now, despite having a fair few Android 1.6 or 2.x devices to choose from, UK owners didn't have (legitimate) access to Google's Maps Navigation beta, with its free turn-by-turn directions. That's all changed today, with an unannounced overnight update delivering the 4.1.1 Beta (that hit US Android phones back on April 6th) to UK handsets.
As with the US version, the app supports verbal directions together with 2D and 3D mapping views; you can choose to view directions as normal, or tap over into "Navigate" mode which looks more like a standalone PND. Various overlays are possible, including ATMs and fuel stations.
If you've a Nexus One, you'll also be able to use the voice command functionality to enter a destination without using the onscreen keyboard: just say "Navigate to" and wherever it is you want to go. Screenshots in the gallery below.