Where is Edward Snowden? Russia, Cuba, Ecuador? The location of the NSA whistle-blower has excited the media this week, but beyond the spy-thriller plot line, the affair has also reignited one the key debates of our time - namely what is the value of personal privacy in a digital world?

Snowden’s leaks about the extensive secret surveillance being conducted by both the United States and British governments has alarmed many, but I’ve been struck by the public’s general lack of surprise at the revelations.

We have not seen baying mobs at the gates of Downing Street, demanding that heads must roll. However, it would be a mistake to see their absence as an implicit acceptance by the general public of a new privacy paradigm now being in place, of a personal data free-for-all.

” Transparency will be crucial if the industry wants to use personal data”

As with the phone hacking scandal, we have yet to see a Milly Dowler moment when an obscure issue seen as affecting the minority comes into sharp relief for the majority. It would be naïve to assume that moment won’t come for the privacy debate in the UK.

When it does, the retail industry will not be immune from scrutiny. Speaking at an IBM event that took place earlier this month, former Tesco CEO Sir Terry Leahy reiterated his belief that the future for retailers lies in them using personal data to engage individual customers in order to find out how they can be most useful to them. It’s a maxim that he himself applied with astounding success through Tesco’s Clubcard scheme.

That said, the Clubcard, with its famous (or should that be infamous?) ability to know you’re pregnant before most of your family do, is still regarded as rather sinister by a significant minority. So many of the important digital trends and technologies that I’ve discussed in this column have third-party access to personal data at their heart. Most make loyalty cards look positively unobtrusive by comparison.

If brands and retailers want to be “the most useful” to their customers by harnessing whole new levels of real-time personal information, transparency will need to be paramount.

The public are not naïve and most increasingly understand that their personal data is a commodity that not only delivers value to retailers and brands, but also to them. In the years ahead, it will be more important than ever for retailers to communicate the mutual value of that exchange to consumers and not just assume it is a given.

The sharing of personal data will be the retail industry’s grand bargain, but one that both sides will need to consent to.

Daljit Bhurji is MD of integrated communications consultancy Diffusion