The article says:

unless it can be proven that the recipient consented to them or was a customer – with John Lewis unable to satisfy either requirement

So it sounds like in this case he didn't actually purchase anything.

I've never been a big fan of the "existing business relationship" rule. It basically means I have to click an unsubscribe link once for every company I buy from.

When does an "existing business relationship" end? If I buy a £1 widget for auntieswidgetstore.co.uk, do they have an "existing business relationship" until the day I die?

In my books, once payment has been made, the goods received, and the sales contract completed, the business relationship is over. Comments? Anyone here a (British) lawyer?

IANAL but the ICO has a readable summary. They say you should be given a simple way to opt out in every communication:

from http://ico.org.uk/concerns/marketing/11

The law says that marketers are allowed to send marketing messages if:

the marketer has obtained your details through a sale or negotiations for a sale (this includes asking for a quote); the messages are about similar products or services offered by the sender; and you were given an opportunity to refuse the marketing when your details were collected and, if you did not refuse, you were given a simple way to opt out in every future communication.

To me it sounds like John Lewis met all of those conditions. I can see there might be some grey area in the first one. But I would argue that when the guy signed up on their site, he was at least taking the first step in negotiations for a sale. But it seems John Lewis argued that and lost so I guess I would lose too.

Edit to add: I do think that pre-checked opt-ins are a bit sleazy.

What if there's a recall of those widgets? What if the company's DB is compromised and they need to notify you of a possible privacy breach? There has to be some leeway for contacting someone with whom you've done business online.

EU law makes a distinction between service emails and emails with a commercial message.

A recall message (we've noticed a problem with a widget you have) is perfectly legal, while a message like "since you're an avid user of our widget we present you widget v2" isn't.

Do you expect any kind of warranty with your widget? Should the relationship be considered to be ongoing if you might go back in the future for service or advice?

You might just want to maintain a wish list which others can make use of. There might be other legitimate reasons for having a user account and not a 'business relationship'. I’ve always been taught that 'opt out' is illegal, so this is a welcome ruling, IMO.