What it means for a UK law firm
Large language models are the technology behind ChatGPT, Microsoft Copilot, Google Gemini and Claude. A large language model does not look facts up by default: it generates the text that is most likely given its training and the prompt. That is why a large language model can write a convincing paragraph about a judgment that was never handed down.
For a UK law firm, the practical questions about a large language model concern how it is deployed rather than the model itself: whether the provider trains on the firm's data, how long prompts and responses are kept, where processing takes place, and whether answers are tied to source documents.
Example
Illustrative scenario
A solicitor asks a general-purpose chatbot for the limitation period for a type of claim. The large language model gives a confident answer with no source. The solicitor confirms the period in the Limitation Act 1980 before advising, because the model's answer is a prediction, not a lookup.