Clients want the saving, and agencies already use the tools
Nine in ten agencies use generative AI and fewer clients pay for hours. The saving is real on routine text and unproven for the business as a whole.
What to say when a client asks for the saving
Three measured results are safe to quote.
- Routine writing is faster. Professionals with ChatGPT finished mid-level writing tasks 40% faster, and graders rated the output 18% higher (Noy and Zhang, Science, 2023, 453 people).
- Routine marketing email can match staff writers. In three trials at one US wine retailer, emails written by a model sold as much as emails that took a staff writer about three hours each (Chicago Booth Review, July 2026).
- Experts gain least. In customer support, novices with an AI assistant resolved 34% more issues an hour and experienced staff gained little (Brynjolfsson, Li and Raymond, 5,179 agents).
One result is a warning. A UK government department that gave 1,000 staff Copilot reported: "We did not find robust evidence to suggest that time savings are leading to improved productivity." (Department for Business and Trade, August 2025)
A script for the meeting:
We use AI on the routine text, and that part is faster. You will see it in turnaround and in the number of variants. The idea, the facts and the check are still done by people, and that is the part you are paying us for.
Before the meeting, read the AI clause in the contract. If there is none, ask the client what they expect to be told.
Almost every agency and advertiser now uses it
| Who | Figure | Source |
|---|---|---|
| US marketing agencies | Nine in 10 use generative AI | Forrester with the 4A's, 24 June 2026. MediaPost reports 87% and a sample of nearly 200 agency decision-makers. |
| UK advertisers | 99% are engaging with generative AI. 14% report significant business impact. | ISBA, 22 July 2026, 200 responses |
| Copywriters in the UK trade body's survey | 74% use generative AI, up from 59% two years before. 35% are obliged to by a client, colleague or employer. | ProCopywriters Survey 2026, 573 copywriters |
The stated aim is cost, and the trade studies call that the weaker aim
In the US study, 81% of agencies name staff productivity as the goal. 61% treat AI as a cost of business. 6% treat it as a line of business that they sell to clients (MediaPost, 6 July 2026).
In the UK, 76% of advertisers name efficiency as the main aim, up from 65% in 2025 (Marketing Week, 22 July 2026).
Forrester's analyst Jay Pattisall, in the release:
"AI has fundamentally transformed marketing agencies, but the industry is at risk of mistaking efficiency for effectiveness."
Fewer clients pay for hours
- Among 69 multinationals, labour-based fees were the standard model for 33% in 2022 and 17% in 2026. Fixed-fee or output-based models are now 35%. In the US and Canada, labour-based fees are still 38% (WFA and Agency Mania, reported by Marketing-Interactive, 27 September 2026).
- 39% of CMOs plan to cut agency spending. 22% say generative AI has reduced their reliance on agencies for creativity and strategy (Gartner, 12 May 2025, 402 CMOs in North America, the UK and Europe).
- 63% of UK advertisers say their relationship with content production agencies changed in the past year because of generative AI (VideoWeek on ISBA, 22 July 2026).
WPP's chief executive, Cindy Rose, to Digiday on 6 August 2026:
"the time and materials model is probably not sustainable in the long term because AI ultimately will enable us to do our work faster with fewer people"
Agency headcount is down, and writing roles are down most
- UK IPA member agencies employed 26,787 people in September 2024 and 24,963 a year later, a fall of 6.8%. Creative and other non-media agencies fell 14.3%. 8% of agencies say they cut staff as a direct result of AI, and 24% expect to in the next 12 months (IPA Agency Census 2025, 11 February 2026).
- Writing roles were 17% of agency job postings in one six-month period and 6% in the next six months. In July 2026 they were 3%, the lowest month since 2022 (The Drum, 9 September 2026, from Agency by Agency data).
- The median day rate in the ProCopywriters survey rose 10% in two years, to £440 (ProCopywriters). The survey reaches working copywriters, so it does not count those who left.
Four in ten agency contracts say nothing about AI
- 39% of agency contracts do not mention AI, and 27% mention it only in broad terms (Adweek, 19 February 2026, 501 decision-makers in the US and Canada).
- The US advertisers' body has a standard rider. The agency must tell the client when it uses AI and must not pass AI work off as human work (AdExchanger, 17 July 2025).
- The UK bodies agreed the same principle in 2023: neither side puts AI-generated content into work for the other without agreement (IPA and ISBA).
- Some clients forbid it. Studio Dumbar/DEPT says that about 80% of its clients "strictly forbid us to use AI in the end product", for legal reasons (Design Week, 13 October 2025).
- Base Design has a written AI policy, and it uses language models "for language in decks, research, insights" (Design Week, 6 October 2025).
- We read the websites of 28 brand and design agencies on 7 October 2026. None publishes a policy on disclosure of AI-written copy.