Virgin Media has finally begun converting customer Super Hubs into public Wi-Fi hotspots. Some customers have reported receiving an e-mail from Virgin, letting them know that their home router is now broadcasting a public Wi-Fi signal. Virgin Media is opting in "hundreds of thousands" of customers by default, but you can opt out after the fact.

A little background: a couple of years ago, Virgin Media started trialling a public Wi-Fi service very similar to "BT Wi-Fi with FON," where residential BT customers have their routers turned into hotspots. For some reason the broad rollout of Virgin's service was delayed until now.

There are some curious differences between BT and Virgin Media's approach, though. For starters, it seems only Virgin Media customers will have access to this nationwide Wi-Fi network; BT grants free access to BT customers, but non-customers can pay for access (£4 per hour). The owner of that subverted hotspot doesn't get any of the money, of course.

Furthermore, while BT customers must share their ADSL or VDSL bandwidth with any public Wi-Fi users, Virgin Media promises that "your home network is completely separate from Virgin Media WiFi traffic, meaning the broadband connection you pay for is exclusively yours, and just as secure."

Presumably, when a customer's Super Hub is added to the public Wi-Fi service, it connects to the local DOCSIS network at a slightly higher rate. So, for example, if you pay for a 200Mbps Virgin Media package, your modem might actually connect at 220Mbps, with the extra 20Mbps reserved for public Wi-Fi users. We've asked Virgin for more details and will update this story if we get a response.

Security-wise, the Super Hub probably creates a separate VLAN for the public Wi-Fi network, just like BT Wi-Fi with FON. In theory, there will be no crosstalk between the two networks, ensuring all data that flows across either network stays private.

One remaining issue, though, is that there will be more local Wi-Fi congestion. Even if you have a dedicated 200Mbps connection to the Internet, if someone outside is hogging the Wi-Fi your laptop might not be able to connect to the router at 200Mbps. Modern 802.11ac MIMO devices should be fine, though.

For now only Virgin Media customers with the latest Super Hub 3 (Hub 3.0) are being opted into the new public Wi-Fi service. Virgin is trialling an update to the older Super Hub 2ac routers, too. The ISP says it will add "hundreds of thousands" of hubs by "later this year."

Virgin Media customers can opt out of the service by logging into My Virgin Media and going to My Profile. When the service was first trialled in 2015, those who opted out of sharing their own router were then banned from using other Virgin customers' hotspots. We have asked Virgin Media to confirm whether that's still the case.

If you're a Virgin Media customer who wants to use the new free Wi-Fi network, download the Virgin Media WiFi app on iOS or Android. (Presumably Windows and Mac laptop users can still log in somehow, though.)

Now read our deep dive into the legal issues of operating a public Wi-Fi hotspot...