There is currently no standard rating system for car seat safety performance. However, by law any child seat sold in the UK must have passed the European Commission's (EC) 44.03 or later 44.04 standard for child seats.
The 'E' mark (a capital E in a circle) will confirm this, and provides the assurance that the car seat will help to protect an infant in the most common crash scenarios.
The Transport Research Laboratory (TRL) has launched its own independent testing programme, with a maximum five-star rating for the safest seats.
The programme tests the seats more rigorously than the tests required for EC type approval, and includea side impact and usability as part of the scoring (neither of which feature in the EC test).
However, at present the results are published only at the discretion of the seat manufacturers, many of which are simply using the results to help them improve their products. Some manufacturers may claim that their seat is safer than others, but there is currently no way of knowing this for certain.
When choosing a car seat, bear in mind that cost is not an indicator of safety alone. Many seats cost more because they offer certain practical features, more comfort for your child or just better quality fabrics or a more fashionable design.