Adverts from broadband providers will soon have to show the average rather than the top speeds they offer, under new rules to take effect from next May.

The Committees of Advertising Practice (CAP) has decided that speed claims in broadband ads will have to be based on "average" speeds, defined as the download speed available to at least 50% of a company's customers between 8pm and 10pm.

Currently, 'up to' speeds quoted in adverts only have to be achieved by at least 10% of customers.

The changes, which will take effect from 23 May 2018, will apply to adverts for residential broadband services.

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Speed-checking facilities should be mentioned in ads

In addition to changes to the way speeds are advertised, the CAP also said that broadband speed-checking tools should be promoted in ads wherever possible.

These tools, such as Ookla's, allow users to get an indication of their download speed – the rate at which you get data from the web – and upload speed – the rate at which you can send data to the web.

The CAP also announced the outcome of its review of fibre claims in broadband advertising, concluding that it is not misleading to describe broadband services that use fibre-optic cables for only part of the connection to consumers' homes as "fibre broadband".

However, it advised advertisers not to state or imply a service is the most technologically advanced on the market if it's a part-fibre service.

Changes to give a 'better understanding' of broadband speeds

Shahriar Coupal, director of the CAP, said: "There are a lot of factors that affect the broadband speed a customer is going to get in their own home – from technology to geography, to how a household uses broadband.

"While we know these factors mean some people will get significantly slower speeds than others, when it comes to broadband ads, our new standards will give consumers a better understanding of the broadband speeds offered by different providers when deciding to switch providers.

"We continually review our standards to make sure they reflect consumers' experiences, the technology available and the evidence base to make sure our standards are in the right place. Following extensive research and consultation, we hope our new standards will improve customer confidence in future ads."