Virgin Media has begun trialling a particularly ingenious form of free public Wi-Fi, called smart pavements. In Chesham, Buckinghamshire, Virgin has installed wireless routers underneath its manhole covers, where they can be wired into its core network directly. According to Virgin, some shoppers are already reporting download speeds of around 20MB/sec (166Mbps), which is not bad for free, public Wi-Fi.

Virgin, like BT, maintains a large network of ducts, access points (manholes), and cabinets across the UK. Now, Virgin seems to have realised that it might as well cram a Wi-Fi router into its access points and cabinets, and provide free Wi-Fi to whoever might be nearby.

While a below-ground manhole might not seem like the most obvious place for a router, Virgin says that a range of around 80 meters (260 feet) is possible. This is probably due to specially designed/shaped antennas, and a "specially developed" resin manhole cover that doesn't attenuate the wireless signals as much as a cast-iron cover would.

We don't know the exact details of Virgin's deployment in Chesham (population: 21,000), but it sounds like there's just a single smart pavement, in the centre of town. The rest of the coverage is provided by Wi-Fi routers hiding in "discreet street furniture" and in Virgin's above-ground cabinets. (As an aside, we also think that calling an object "smart" just because it contains a wireless router might be stretching things a bit.)

Along with free public Wi-Fi in Chesham, Virgin is also (finally) experimenting with providing a competing service to "BT Wi-Fi with Fon," where Virgin Media subscribers have their at-home (or at-work) cable routers turned into Wi-Fi access points that can be used by other, roaming Virgin customers. You can opt out of this service through your online Virgin Media control panel, but then you won't be allowed to use other free hotspots either. Virgin appears to be trialling the service in some parts of the M4 corridor, before deciding to roll it out to the rest of the country.

There's no word on when other towns might get the smart pavement treatment, but with Virgin Media currently going through a period of expansion, and the ease of whacking a few wireless routers in cabinets/manholes around the town centre, we'd be surprised if Virgin doesn't go for a few more relatively inexpensive PR coups in other towns around the country.