I love Three's new WiFi Calling feature (well, it's an Apple feature, but Three finally decided to support it!) – ultimately it lets me use my phone (most of the time) at home for calls and SMS (think 2FA!) where there is no signal on Three.

However, I recently discovered a big issue. With "Show My Caller ID" turned off calls I make are not withheld. That is the called party can see my, supposedly private, Caller ID.

The Law

Ofcom wrote to all UK CPs a number of years ago reminding them of their responsibilities, part of this eMail included;

CPs must respect the privacy rights of consumers and adhere to these rules subject to the exemptions that exist. Under PECR, the CP may override anything done to prevent the presentation of the identity of a calling line where necessary to investigate and trace malicious or nuisance calls and where calls are made to emergency services (calls to 999 or 112).

In all other circumstances, a consumer’s right to withhold their number is absolute. We have received complaints from consumers who have advised us that despite taking the appropriate steps to withhold their number, there have been instances where their number was displayed to the called party.

Failure to apply the privacy markings upon request is likely to constitute a breach of GC 16 and/or PECR and Ofcom and the ICO, as appropriate, will consider using our powers to take enforcement action where such failure occurs, including opening investigations as appropriate.

So Ofcom's view would seem to suggest that Three are acting unlawfully.

However, trying to point this out to Three has achieved nothing so far - so we'll see if I have any more luck with Ofcom who were contacted today regarding this.

How do I know?

Additionally, this is a bigger concern as the “WiFi Calling” feature is transparent to the end user - there is no way of knowing if this technology, or the normal cellular signal, is being used when placing a call (indeed the device will often use WiFi Calling when a mobile signal is available, resulting in an otherwise withheld number being displayed)

Protecting your CLI

The only way to be absolutely sure that your privacy is protected is to switch off WiFi Calling. However, this is no use to people like me who are then left without phone service (short of using an app like Acrobits Groundwire and a SIP provider)

What Next?

Three, if you're reading this please fix this, but don't 'fix' it by breaking or turning off WiFi Calling, it's a lifeline to those who live in remote areas!