During the 18th and 19th century debates about advertising were mostly about advertising excesses and decency. From the 1970s onwards another concern emerged: privacy. Computers made it possible to collect, store and process huge amounts of personal data. As computer technology became ever more powerful and widespread the government eventually decided (reluctantly) that legislation was needed to protect people's privacy. The result was the Data Protection Act 1984, introduced by the Thatcher government. The act established a Data Protection Registrar (the predecessor of the Information Commissioner) and gave people the right to ask organisations what personal data they store about them (the so-called right of access).

For us junk mail haters, the Data Protection Act 1998 is much more relevant. Section 11 of the Act introduced the right to prevent the processing of personal data for "direct marketing" purposes. As you would expect, the section is written in proper Legalese:

Right to prevent processing for purposes of direct marketing

1. An individual is entitled at any time by notice in writing to a data controller to require the data controller at the end of such period as is reasonable in the circumstances to cease, or not to begin, processing for the purposes of direct marketing personal data in respect of which he is the data subject.
2. If the court is satisfied, on the application of any person who has given a notice under subsection (1), that the data controller has failed to comply with the notice, the court may order him to take such steps for complying with the notice as the court thinks fit.
3. In this section “direct marketing” means the communication (by whatever means) of any advertising or marketing material which is directed to particular individuals.

The rules for enforcing this right were fairly strict. You had to ask a data controller (such as a junk mailer or list broker) to stop (or not begin) processing your personal details for "direct marketing" purposes in writing and refer to the Data Protection Act. The Information Commissioner's website used to have a page about stopping junk mail, which included an example data protection notice:

Parliamentary debates

The introduction of the right to object to direct marketing was largely uncontroversial. For instance, in February 1998 Viscount Astor (Conservaties) gave the Act a guarded welcome. He was concerned about the burden the bill would place on businesses and the estimated cost but he supported the introduction of the right to prevent processing personal data for "direct marketing" purposes, which at the time was known as Clause 10 (it would eventually be Section 11):

I welcome the introduction of the rights of the individual in Clause 10 with regard to direct marketing and I concur with what the Minister said. How much that will stem the flow of useless junk mail which pours through our letterboxes is not clear, but at least it is a valid attempt to try.

As is reasonable in the circumstances

The debate in the Lords about the right to object largely focussed on details, and not on the principle. This resulted in one change. Section 11(1) originally read:

An individual is entitled at any time by notice in writing to a data controller to require the data controller to cease, or not to begin, processing for the purposes of direct marketing personal data in respect of which he is the data subject.

An amendment by Lord Williams of Mostyn added the subordinate clause "at the end of such period as is reasonable in the circumstances to cease". It was generally accepted that junk mailers would have to comply with an objection within three to four weeks, and Mostyn argued this might be too inconvenient for them:

If a data controller's plans to begin processing are very far advanced it may be very onerous to expect him to bring those plans to an instant halt in every case where he receives a notice of objection. These amendments in effect introduce a requirement for reasonable notice in such circumstances. The amendments, however, do not say that it will never be right to expect a data controller to bring his plans to an instant halt. In some cases it may well be reasonable to expect a data controller not to begin at very short notice, but not always. Much will depend on individual circumstances.

The amendment, which was accepted, is interesting. Mostyn effectively argued that it would be unfair to expect an advertiser to suppress a junk mail letter after it had started planning an ad campaign. It is not quite clear why this would be unfair. Buying a mailing list doesn't grant a marketer the God-given right to target everybody on that list — it is entirely reasonable to expect the advertiser to remove the names and addresses of people who have used the right to object, even late in the production process.

Whatever the exact thinking behind the amendment, the same argument is used by industry-run opt-out schemes. Royal Mail's Door-to-Door Opt-Out becomes fully effective after six weeks, while the DMA's Mailing Preference Service and Your Choice Dummy Scheme allow themselves a full four months to comply with opt-out requests. There is no good reason for this. The MPS website explains that the four month wait is needed because companies prepare their mailings months in advance and because screening usually takes place early on in the mailing process. However, that is a choice. They could do a final screening exercise towards the end of the "mailing process". It would make sense to do so, as it would make the MPS more efficient and customer friendly. The only reason they don't do this is because it would be a minor inconvenience.

A requirement to respond in writing

Lord Mostyn also moved an amendment that would require data controllers to respond to a Section 11 notices within 21 days. Without this, people wouldn't know if their objection had been received and acted upon:

Amendments Nos. 21 and 24 are further government amendments and are designed to address points made by the noble Lord, Lord Norton, in Committee. He pointed out that in Clauses 9 and 10 there was no requirement for the data controller to respond to a written notice from an individual objecting to processing. Without such a response the individual would have no means of knowing whether his objection had been successful or, if unsuccessful, why it had been rejected. A requirement to respond in writing to a notice of objection would provide a link between the data controller and the data subject and hence the opportunity for dialogue before the data subject needed to consider involving the commissioner or referring the matter to the courts.

This amendment wasn't accepted. On 24th March 1998, Earl of Northesk (Tory) told the Lords The Direct Marketing Association had promised to add a requirement to acknowledge data protection notices in its code of practice. That was good enough for the government, even though the DMA is a voluntary membership organisation (there are lots of junk mailers who aren't members of the DMA). Anyway, this is the assurance the Earl of Northesk had received from the DMA:

The DMA undertakes to provide in its Code of Practice that any written notice by a data subject under Section 10(1) of the Data Protection Act 1998, other than a notice using or forming part of transactional or other commercial documentation, must be acknowledged by the data controller in writing to the data subject as soon as is reasonably practicable.

The requirement was added in version 3 of the code, in September 2003. Non-DMA members had to follow the Information Commissioner's Office's guidance, which advised that it was good practice to acknowledge [Section 11 notices] and confirm that the marketing will stop. However, the guidance explicitly stated that acknowledging such notices wasn't required.

Do opt-out boxes count?

The above-mentioned Earl of Northhesk also raised the issue of opt-out boxes. Specifically, he wanted to know if ticking an opt-out box to prevent unwanted junk mail would have the same status as sending a data protection notice under Section 11 of the Data Protection Act. He was not a fan of the idea:

As the Minister will be aware, a widely used practice in the direct marketing industry is that of offering the customer the opportunity of indicating his wish not to have his data further processed by means of an opt-out tick box. That methodology has distinct advantages. It is simple, concise and clear to both the customer and the business concerned. At issue here is whether it is intended that such tick boxes should be interpreted as being data subject notices. Legal advice obtained by the British Retail Consortium indicates that they should be. If that is the case, it will have the inevitable effect of adding considerably to the administrative costs of, for instance, the mail order catalogue industry.

The isolation of negative option ticks from the volume of orders processed within the specified time frame of 21 days would involve extensive extra work and cost. Moreover, on the basis that that system has operated well enough to date, it is highly unlikely that any real benefit would accrue to the data subject in those circumstances. In fact, he could be severely inconvenienced in the event that, on strict interpretation, he may be required to send any written objection to further processing separately from his having ticked the opt-out box.

The Earl had also received assurances from the DMA on this front. They would require DMA members to take such steps to comply with the requirement under Section 10(1) as he considers appropriate. In other words, it would up to individual junk mailers to decide whether or not ticking an opt-out box counted as a Section 11 notice.

But what about poor charities?

Of course, the charity argument was also wheeled out. On 23rd February 1998 Baroness Young of Old Scone proposed to change the definition of "direct marketing" so that it wouldn't apply to charities.

[…]in many cases when the not-for-profit sector is communicating with supporters or members, it is doing so in a way which is dual purpose. It is primarily providing factual information on its work or on issues in which it and the data subjects have a mutual interest. It may at the same time also be soliciting support in that issue. This support may be of a financial nature but it could equally be of a non-financial nature. I am talking about circumstances when voluntary organisations and charities, for example, send out briefing material to supporters on issues and perhaps ask them to return cards saying that they are concerned about that issue, so that the degree of that concern can be communicated to Government or other opinion formers or decision makers. It is really to seek assurance from the Minister that he will consider whether a more detailed definition of marketing material may be inserted into the Bill to ensure that legitimate material coming from the voluntary sector, which I believe is in the public interest, will not be disbarred by this provision in the Bill.

This was promptly rejected and the Baroness withdrew her amendment:

[Baroness Young of Old Scone] rightly observed that direct marketing is defined in the Bill as encompassing all advertising and marketing material directed to particular individuals. It is not simply the bargain offers for 300 tulip bulbs – "Hurry while stocks last" – that irritates people. Individuals find other forms of advertising – some from non-profit-making organisations, some from religious organisations, some from what many of us would call fringe or cult organisations – of irritation sometimes; some people evidently find them of fascination.

All that this does is to give citizens the right to prevent all kinds of intrusive direct marketing material being sent to them by any means. It does not stop any data controller entering into the process and sending out the material; indeed, he is perfectly entitled to do so. On the other hand, citizens who do not wish to receive this material to which they are entitled, are now, quite rightly, able to say, "Do not send me this material"; in other words, they have the right to prevent such processing for direct marketing purposes. We do not see any reason to draw a distinction between those who are doing the processing. We are protecting here someone who does not wish his data to be used in this way, with the consequence of having material which may or may not be junk.

Data protection notices in the wild

Although the right to object was somewhat watered down, it remained an effective way of stopping (or preventing) addressed junk mail. A data protection notice could be an email and a signature wasn't required. You just needed tell a junk mailer, in writing, that you were enforcing your rights under section 11 of the Data Protection Act 1998. Junk mailers had to comply with these requests — failing to do so was a breach of the Data Protection Act. That is quite different from voluntary, industry-run opt-out schemes such as the Mailing Preference Service, where you just have to hope for the best.

The downside of data protection notices was that using them was a hassle. You had to contact junk mailers individually and keep a record of your request (without a record you wouldn't be able to enforce your rights). In practice, data protection notices were mainly used to force the most obnoxious junk mailers to stop harassing you. If you kept getting, say, begging letter from a certain charity then you could force them to stop.

Beyond this, some commercial opt-out schemes, such as Opt-Out UK and ALLOW, let users generate and sent data protection notices to both junk mailers and list brokers. And, some electoral registration offices started encouraging voters to use the notices to opt out permanently of being included on the for-sale copy of the electoral register — a good example is this notice produced by Cheshire West and Chester Council. Forms like these were a response to the Direct Marketing Association moaning about local councils carrying forward opt-out preferences. The junk mail lobby group felt it was legally unsafe for election administrators to pre-tick the opt-out box on the annual canvas if an elector had previously opted out — they argued a fresh opt-out opportunity had to be made during each and every annual canvas. (Eventually, the junk mail lobby lost that particular argument when Individual Electoral Registration was introduced in June 2014. Opt-out preferences on electoral registration forms are now always carried forward.)