Artificial intelligence is now used by almost 90% of legal professionals in the U.K. and Ireland, and it's putting one of the profession's oldest conventions — the billable hour — under the microscope.
That's according to legal software company Clio's U.K. & Ireland Legal Insights Report 2026. It found that among firms using AI, almost 80% said they can handle more work without increasing resources, while over 70% said it cut costs by absorbing administrative work once done by support staff.
As a result, AI is challenging some of the assumptions on which the legal profession was built, forcing firms to reevaluate how their lawyers spend their time, how they charge for it and how new lawyers learn the ropes.
Some of the U.K.'s biggest firms are already putting this into practice. A&O Shearman has worked with legal AI company Harvey to develop artificial intelligence agents for tasks, including reviewing loan agreements and analyzing regulatory filings, which it says can complete in minutes work that previously took several hours. Slaughter and May, meanwhile, has rolled out Harvey across all practice areas this year, including for regulatory research and document analysis.
The billable hour is central to the business model of many law firms, but when AI significantly reduces the time lawyers spend sifting through and drafting documents, the economics are no longer so straightforward.