Note: This advice is given by the CAP Executive about non-broadcast advertising. It does not constitute legal advice. It does not bind CAP, CAP advisory panels or the Advertising Standards Authority.

The ASA has investigated, and upheld against, many comparisons made by telecoms companies claiming superiority over competitors. Marketers intending to make any comparisons should consider how consumers are likely to interpret the claim in the context of the ad.

Claims that the average consumer is likely to understand as an obvious exaggeration (puffery) or claims which consumers are unlikely to take literally are allowed provided they do not materially mislead (Rule 3.2).

If consumers are likely to understand a claim as an objective claim, the advertiser must hold evidence to substantiate the claim as consumers are likely to understand it (Rule 3.7).

All claims which draw a comparison with identifiable competitors must also comply with Rules 3.33-3.40.

Before making any comparative claims in advertising, marketers should consider the following:

  1. How will consumers interpret the claim?
    • Is it puffery?
    • Is it an objective claim?
    • Is it a comparison with identifiable competitors or unidentifiable competitors?
  2. If it is objective, make sure you can substantiate it.
  3. In addition, when making a comparison with identifiable competitors, comply with rules 3.33 – 3.37.

The sections below give detailed guidance on each of these stages, before finally focusing on a particular type of comparative claim especially relevant for broadband and telecoms: ‘fastest’ internet speed claims. This advice is designed to be read alongside our general advice on Comparisons: general.

How will consumers interpret the claim?

​​​​​​Is it puffery?

Obvious exaggerations ("puffery") and claims that the average consumer is unlikely to take literally are allowed provided they do not materially mislead.

Marketers are not expected to hold documentary evidence to prove such claims unless consumers will view them objectively, and they are capable of objective substantiation. The ASA will assess a consumer’s likely interpretation of a claim, rather than the marketer’s intention. Marketers should take care to ensure that any obvious exaggerations will not be understood as objective claims.

For example, the ASA considered “the perfect network” to be an objective claim. The ASA considered that consumers would understand it to be an objective claim that Sky Mobile performed to a very high standard across a range of network related factors. Additionally, because the ads claimed that Sky Mobile was “the perfect network”, consumers would understand the claim to mean that Sky Mobile was the only network which could be described as “perfect”. Given the advertiser had argued the claim was subjective, no objective evidence was provided, and the ASA concluded the claim had not been substantiated (Sky UK Ltd, 8 June 2022).

Is it an objective claim?

Claims that consumers are likely to take literally are likely to be interpreted as objective claims.

By way of example, in 2018 the ASA considered that consumers would interpret the claim “The UK’s best value mobile” to relate to the features integral to the nature of a mobile phone service: minutes, texts and data, all of which can be measured objectively. As the advertiser did not offer more data, minutes and texts than all other UK mobile tariffs relative to the costs of the tariffs, the ASA found the claim to be misleading (Utility Warehouse Ltd, 08 August 2018). See also “best price” (The Carphone Warehouse Ltd, 03 August 2016).

Is it a comparison with identifiable competitors or unidentifiable competitors?

Ads do not need to explicitly identify the competitor or product being compared to be subject to the rules on comparisons with 'identifiable' competitors. See ‘identifiable competitors’ below, and Comparisons: identifiable competitors.

If it is not possible to identify a competitor, rules 3.33 – 3.37 will not apply. Marketers must still ensure that these types of comparisons do not mislead (rule 3.38), and objective claims must be supported by evidence (rule 3.7). See Comparisons: general for more information.


The nature of the evidence required to substantiate any objective comparative claim will vary depending on how it will be understood in the context of the ad. For example, after investigating Virgin Media’s use of the term ‘Get the fastest WIFI Guarantee of any major provider’, the ASA said the claim had not been substantiated as it would be understood by consumers, as consumers would understand the claim to mean that Virgin Media guaranteed the fastest WIFI service of any major broadband provider. In fact, Virgin Media’s claim related to their offering of a guarantee which promised action by the advertiser if a minimum speed (i.e. a guaranteed speed, which was higher than any other speed subject to a similar guarantee by any other provider) was not met (Virgin Media Ltd t/a Virgin Media, 13 December 2023).

Superlative claims are likely to require substantiation. In August 2023, after a detailed analysis of a data subset produced by RootMetrics, the ASA accepted that various ‘No 1 for 5G’ claims had been substantiated by EE. However, a number of the ads were still deemed misleading, as the ads implied the ‘No 1 for 5G claims’ had been based on ‘RootScore’ reports, which did not relate specifically to 5G network performance, rather than the applicable data subset (EE, 23 August 2023).

Top parity comparisons claim that a product and/or service is just as good as any alternatives. For example, “you won’t get a better Wi-Fi signal” was considered misleading because the advertiser could not substantiate that their Wi-Fi hub performed as well as the other major broadband providers (TalkTalk Telecom Ltd, 10 July 2019).

The ASA also investigated “Bristol. Don’t settle for Virgin. Get Ultrafast Full Fibre with more reliable speeds than Virgin M200 and M350”. Although the advertiser could demonstrate that the service had more reliable speeds nationally, the data provided by way of substantiation could not be extrapolated to demonstrate that this was the case on a local level and the claim was considered misleading (British Telecommunications plc t/a BT, 05 May 2021).

Self-reported consumer data will not be sufficient to support objective claims. Marketers should not rely on consumer perception data, or on the fact that they have received awards, to support claims lacking objective substantiation. In one example, the ASA considered that consumers would understand the claim “Best network for data” to be based on a comparison of a range of mobile-data-related performance measures (i.e. coverage, speed), from a range of mobile data networks. In reality, the claim was based on Three receiving an award, which was decided by a panel, and a consumer survey. The ad lacked the objective substantiation required (Hutchison 3G UK Ltd t/a 3, 24 February 2021).

For further advice on comparative claims made based on surveys and awards see Comparisons based on awards and consumer surveys.

Identifiable competitors

Comparisons with identifiable competitors “must not mislead, or be likely to mislead, the consumer about either the advertised product, or the competing product” (rule 3.33), “must compare products meeting the same need or intended for the same purpose” (rule 3.34), and “must objectively compare one or more material, relevant, verifiable and representative feature of those products” (rule 3.35). See Comparisons: Identifiable competitors for more information.

The ASA has upheld complaints about comparisons with identifiable competitors, under rule 3.35. The claim “on the network voted Britain’s Best for Coverage” breached this rule because it was not based on a robustly conducted comparison of a range of appropriate, relevant and objective criterion (Telefonica UK Ltd, 22 September 2021). Similarly, in July 2023, the ASA found an ad which compared the price of Sky’s broadband package with BT’s to be in breach of rule 3.35, as at the time the ad was run, BT’s package was discounted, meaning the saving advertised in the ad would not have been achieved (Sky UK Ltd, 26 July 2023).

To make a claim verifiable (as is required under rule 3.35), the advertiser should set out the relevant information in the ad or signpost how the information used to make that comparison can be checked by the audience. For example, the ASA concluded that none of the EE ads claiming ‘No 1 for 5G’ included sufficient information to allow consumers to check the accuracy of such claims, nor were adequate signposts included setting out how consumers could find the information. The same was true of other EE ads related to network coverage (EE Ltd t/a EE, 23 August 2023). See also Virgin Media Ltd, 4 May 2022. For detailed advice on this requirement, see Comparisons: Verifiability.

The information must also be readily accessible. Providing incomplete information, or information behind a paywall, will be insufficient. See Hutchison 3G UK Ltd t/a 3, 24 February 2021.

Comparisons: internet speed

Various advertisers have attempted to make claims that their broadband speeds are faster than their competitors. Ofcom data is likely to be an acceptable source to support such claims, but marketers should exercise caution in the way they use the figures.

Ensure absolute claims are prominently qualified

An absolute claim such as ‘we are the UK’s fastest major broadband provider’ will most likely require prominent qualifying information. BT challenged such a claim made by Virgin Media, as BT maintained their full fibre 900 Mbps service was available in some locations where Virgin’s Gig1 Fibre service was not, meaning BT would be the fastest major provider for consumers in those locations. The ads made clear, by way of prominent qualifying text, that Gig1 was available ‘in selected cities’, and urged consumers to ‘check availability’. The ASA deemed this sufficient to qualify the headline claim, and concluded that consumers would not understand the ad to mean that Virgin Media were always their fastest broadband option (Virgin Media, 4 May 2022) Conversely, in 2016 the ASA found a Sky ad claiming ‘Fastest peak time speeds measured by Ofcom’ to be misleading. Whilst the ad did not include any explicit claims about the speed of Sky’s W-Fi, the ASA considered consumers would take the ad to be referring to speeds accessible on wireless devices, rather than fixed line broadband only, as was the case. The footnote did refer to ‘fixed-line broadband performance’, but it was not deemed sufficiently prominent, and did not make sufficiently clear that Wi-Fi performance was not included. The amended footnote, which stated ‘Ofcom excludes Wi-Fi performance, which varies by device, home environment and ISP’ was also deemed not sufficiently prominently to counter the headline claim (Sky UK Ltd, 16 March 2016).   

Ensure data reflects real life conditions

In 2014 the ASA upheld a complaint about the claim "UK's fastest Wi-Fi technology” because the testing did not take place under typical home circumstances, and did not consider variables such as router placement, time of day and number of devices. The claim “Faster wireless hub than Sky and BT” was also problematic, as the testing was inadequate due to the limited device and operating systems used, and did not reflect typical consumer situations (Virgin Media Ltd, 10 February 2016).

Similarly, a competitor challenged Three’s claim to be building the ‘UK’s fastest 5G network’. The ASA thought consumers would understand the ‘fastest 5G network’ claim to be offering the best real-world user experience of all UK network operators, even though it related to Three’s network capability. The ASA found that whilst Three may be able to offer higher peak speeds, this would be in certain ideal conditions that would rarely be experienced by consumers in a mature 5G network. The ASA found that features raised by Three would only result in noticeable differences in a minority of cases, and that similar speeds would be achievable by others. Other factors impacting consumer experience were unaccounted for, and at the time of the ad, the 5G take up was so minimal the differences in 5G network capacity was unlikely to result in material differences. The ad was deemed misleading (Hutchison 3G UK Ltd t/a Three, 21 July 2021).

Use relevant and up to date research

It is unlikely to be acceptable to use the most up to date research at the time the ad was created if newer data has since been released. In 2013 the ASA upheld a complaint about an ad featuring the claim ‘’Eight times faster fibre optic broadband’ as the data used as substantiation had since been superseded by new research (British Telecommunications plc, 11 September 2013). When considering a report submitted by Sky to substantiate a ‘’Fastest peak time speeds measured by Ofcom’, the fact the testing had been carried out 18 months previously counted against the content of the report, as some of the tested routers had since been replaced by newer models (Sky UK Ltd, 16 March 2016). 

Similarly, when assessing claims that a provider’s mobile network was the fastest in the Channel Islands, as featured in ads from November 2018 and March 2019, the test report relied upon did show Sure’s average download speeds to be faster than their two largest competitors. However, the report was not specifically designed to capture the fastest network speed, nor was it a guarantee of future fastest speeds, and had been produced in July 2017. The availability of contradictory evidence called into question the age of the report as a basis for such claims, especially given the report was not specifically designed to capture the fastest network speed (Sure (Guernsey) Ltd t/a Sure, 1 May 2019).

Marketers should also remember that comparisons with identifiable competitors need to be verifiable. See Comparisons: Verifiability for more information. For advice on other specific types of claims see: ‘Types of claims: Best’, ‘No.1’ and ‘Leading’. For more information on internet speed claims, see Broadband and Telecoms: Speed Claims

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