The problem, of course, is that every home is different. You might have full-fibre access, or a nearby cabinet with old-fashioned copper running up to your doorstep. As a result, it's hard for internet service providers to give one definitive number on their billboard ads. Still, marketing materials can be deceptive. The ASA consulted on a number of solutions, including an average download speed over a 24-hour period (rather than peak hours) and a range of speeds available to the middle 60 percent (20th to 80th percentile) of customers. The latter was ultimately abandoned because it didn't explain where customers were likely to fall within the range.

The new guidelines will take effect on May 23rd, 2018. They're just that, though — guidelines. It will, therefore, be interesting to see just how many providers fall in line.

The ASA made a similar rule-change last year to simplify broadband pricing. In May 2016, it announced that all providers would have to include line rental in its broadband prices. All of the major ISPs are now co-operating, which has made it easier for customers to manage their bills and compare packages.

Ofcom, the UK's media and telecoms regulator, is conducting a similar review into broadband speeds. In October, it published a consultation with suggested changes to the Broadband Speeds Codes of Practice. These included forcing ISPs to use peak time windows for speed estimates, based on a national sample of their customers. Unlike the ASA's rules, however, Ofcom wants speeds to be advertised as a range. They would be given to customers at the point-of-sale and in relevant after-sale information. The rules would also make it easier for customers to switch if their speeds fall below the minimum guaranteed by their ISP.