We found:
. Direct Line quoted up to 22% more if you're unemployed, compared to our default occupation of researcher.
. LV was the most price-sensitive to occupation quoting brewery workers and private investigators up to 23% more, and a bar manager almost 28% more.
. Oddly, More Than quoted 7% more if you keep your car in a garage than if you park the vehicle on your driveway – none of the other insurers did this.
. Direct Line added an extra 7% (low risk) and 8% (high risk) if you don't own your home, and LV an extra 4% and 5%.
. Direct Line also added an extra 8% and 9% if you have children, but More Than didn't change the quote at all in these situations and Aviva and The Co-operative didn't even ask.
. LV quoted 1% and 3% more if you are single, divorced or separated, rather than married or widowed.
It's unsurprising that driving convictions can really make the cost of car insurance stack up, however, we found the premium hikes can vary widely between different insurers:
. More Than charged up to 55% more for motorists who received a conviction for 'driving without due care and attention', but Aviva only increased quotations by up to 7%.
. Premium hikes for 'exceeding the motorway speed limit' also ranged greatly, from 2% for the low-risk scenario with Aviva, to 19% for the high risk scenario with More Than.
Which? executive director, Richard Lloyd, said:
"The cost of your car insurance can vary dramatically across the market, with some surprising factors affecting the price, so it really does pay to shop around and not automatically accept the first renewal offer from your existing insurer."
To see what made rates go up and down, we got online quotes for five of the largest insurance companies – Aviva, The Co-operative Insurance, Direct Line, LV and More Than. We created a high and low risk scenario by changing the make and model of the car, the drivers age, and their location, and then tweaking other variables to see how the rates change.
The low-risk scenario is a 2012 Ford Focus 1.6 Zetec driven by someone in their mid-40s living in rural Cambridgeshire, and the high-risk scenario is a 2013 BMW 120d Sports Coupé driven by a mid-30s motorist living in Tooting, London
