The U.K. insurance industry has a dominant international presence, suggesting strong competitiveness and performance. Yet, its efficiency and productivity has rarely being investigated. The purpose of this paper is to provide an overview of insurers' performance in the U.K. insurance market from 1996 to 2017, using stochastic frontier analysis to measure efficiency scores and productivity at the firm level. Results show the U.K. insurance industry could improve by about 40% in terms of cost efficiency and by 70% in terms of profit efficiency. In addition, our model reveals a higher cost efficiency score compared to profit efficiency, implying that there are higher inefficiencies on the income side of the insurance industry as measured by our profit function. In terms of total factor productivity (TFP) growth, we report a steady decline over time while on average is negative. By decomposing TFP growth into its underlying components, we reveal that the reported negative trend in TFP growth over time has mainly been driven by the enhanced competition that resulted in a drop in markup, while the scale and cost efficiency has also driven TFP growth down. However, from a positive point of view, we report evidence of both β‐convergence and σ‐convergence in cost and profit efficiency.