every vehicle is designated a 1 to 50 rating based on which car insurance group or band they belong to.
Until January 2010, vehicles were grouped from 1 to 20. The old grouping system was replaced by a more comprehensive system that banded cars from 1 to 50, with one being the lowest and 50 being the highest and most expensive car insurance group.
Group 1 vehicles will tend to be cheaper, low-specification models with smaller engines. Conversely, Group 50 vehicles are high-end high-performance models like Aston Martins.