Driving convictions could double your car insurance The research was based on 4,785,925 quotes isssued from October 1 to December 31, 2012. It found that 19 per cent of those quoted had a driving conviction, with the most common (49 per cent of those with a conviction) being an SP30 (exceeding statutory limit) speeding offence. Based on a sample customer*, a speeding conviction increased premiums by 34%, from £682 to £913. Gareth Kloet, head of car insurance at confused.com, said: "Any conviction will likely cause a change in the cost of car insurance and those with convictions could be paying out hundreds of pounds more than people with a clean licence. If you do have a conviction you must disclose this on your policy. If you don't and you make a claim on your policy, your insurance company could refuse to pay the claim. Top 10 most common motoring convictions (percentage increase after conviction) 1 Exceeding statutory speed limit on a public road (34 per cent) 2 Use of a hand-held device whilst driving (49 per cent) 3 Failing to comply with traffic light signals (24 per cent) 4 Exceeding speed limit on a motorway (34 per cent) 5 Using a vehicle without third party insurance (131 per cent) 6 Driving or attempting to drive with alcohol level above limit (115 per cent) 7 Driving without due care and attention (51 per cent) 8 Driving otherwise than in accordance with a licence (49 per cent) 9 Using a vehicle with defective tyres (69 per cent) 10 Exceeeding passenger vehicle speed limit (34 per cent) Sample quotes based on a 30-year-old female marketing manager in Cardiff driving a Mini Cooper 6,000 miles a year, with five years' no-claims discount, car parked on driveway and no convictions.