The Fine Print UK · PUBLISHED 10 AUG 2026 · VERIFIED 10 AUG 2026 · UK EDITION

Your FOS Complaint Success Rate: 24% Not 37%

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The most surprising figure is that Warwick researchers say the FOS’s published 37% consumer uphold rate for 2023/24 may overstate genuinely successful complaints, which they estimate were closer to 24%.

The number that matters

The central number is 37%: the Financial Ombudsman Service’s published share of complaints upheld in consumers’ favour in 2023/24.

How it quietly costs you

The first money-costing mechanism is classification inflation: some complaints that are substantially rejected are still recorded as “upheld,” which makes the public success rate look better than the real consumer outcome.

Warwick’s study says about 33%–34% of complaints recorded as upheld were inflationary overall, and for banking and payments the inflationary rate rose to 48%.

The impact is that a consumer reading the published rate may think they have about a 37% chance of a win, when the study estimates the genuine chance of a successful outcome was around 24% in 2023/24.

The closest “old vs better” comparison is:

• Published: 37% upheld in consumers’ favour.
• Estimated genuine: 24% genuinely successful.

The second, compounding trap

The second layer is representation disadvantage: complaints brought by professional representatives are more likely to be upheld than direct consumer complaints, which means the odds are materially different depending on how the case is filed.

In 2024/25, the FOS upheld 27% of complaints brought by professional representatives, versus 34% of complaints brought directly by consumers.

That means a consumer who assumes “using a paid representative will improve my odds” may be paying for a channel that, on the FOS’s own published data, does not outperform direct consumer filing on uphold rate.

The long-run cost is lost redress opportunity plus time cost: if a complaint is mis-staged, the consumer may spend months pursuing the wrong route while the issue remains unresolved, and FOS complaint resolution can be slow enough that only 47% of cases were resolved within six months in 2021/22.

What this looks like in practice

Sarah, 42, is a London office manager earning £42,000 a year, with a £18,000 current-account overdraft dispute and a pension on the side; she has about 23 years to retirement and is deciding whether to complain directly or pay a claims/complaints firm.

Three discoveries she would make:

• The published consumer uphold rate is not the whole story: the FOS said 37% were upheld in 2023/24, but Warwick researchers estimate genuinely successful outcomes were about 24%.
• Filing through a professional representative is not a guaranteed edge: in 2024/25, representative-led complaints were upheld 27% of the time, compared with 34% for direct consumer complaints.
• The product she is complaining about matters a lot: across firms, consumer success rates ranged from 2% to 94% in the Which? analysis, showing that the benchmark is not “the average FOS case” but the specific provider and product.

The full cost of doing nothing

For Sarah, the combined effect of Problems 1 and 2 is a materially lower chance of a real win than the headline number suggests, plus the risk of paying for an unnecessary representative route.

A reasonable modelling basis is:

• starting from the FOS published 37% uphold rate for 2023/24,
• adjusting to Warwick’s estimated 24% genuine success rate,
• and recognizing that representative-led complaints were upheld at 27% in 2024/25 versus 34% for direct complaints.

On that basis, the headline cost is not a single universal pound figure, but a 13 percentage-point gap between the published and estimated genuine success rates, plus a further 7 percentage-point difference between representative-led and direct complaints in the most recent annual data.

What to do about it

• Check your complaint route using the FOS complaint guidance and the firm-level data pages on the FOS site, then compare your provider’s recent uphold performance with the overall benchmark.

• Go to the official FOS complaints data pages and find the product/firms section relevant to your dispute.

• Compare your provider’s recent uphold rate with the overall consumer average.

• Decide whether to complain directly before paying anyone else.

• Good looks like a provider outcome at or above the overall benchmark of 34% consumer uphold in 2024/25.

• File the complaint directly with the business first, then escalate to FOS only after the business’s final response, using the FOS’s own complaints process guidance.

• Gather account statements, letters, screenshots, and dates.

• Submit a short written complaint to the firm and keep the reference number.

• Escalate to FOS if needed within the time limit in the firm’s final response letter.

• Good looks like a clear paper trail and no paid representative fee, because direct consumer complaints had a 34% uphold rate in 2024/25 versus 27% for represented complaints.

• Measure delay risk before you proceed, using FOS service and complaints-insight pages to judge whether waiting is worth it.

• Check whether the issue is simple or complex, and whether delay would worsen the financial harm.

• Use FOS published timing/service data to estimate how long resolution may take.

• Escalate only if the expected redress is worth months of waiting.

• Good looks like a case where the likely redress exceeds the cost of delay, especially since only 47% of cases were resolved within six months in 2021/22.

A myth worth clearing up

Myth: The FOS’s published uphold rate is the same as the chance your complaint will truly succeed.

Fact: Warwick researchers say the published 37% consumer uphold rate for 2023/24 may overstate genuine wins, which they estimate at about 24%.

Sources

• https://www.gov.uk/government/consultations/fs-sector-strategy-review-of-the-financial-ombudsman-service/review-of-the-financial-ombudsman-service-consultation-accessible

Researched 2026-08-10.

Corrections & disclosure: an AI-assisted, human-reviewed guide. Every figure is dated and sourced above. Spot something out of date or wrong? Tell us and we’ll correct it — corrections are noted here and in the video description.