The 12-month policy will generally start on the date that the last car insurance is up for renewal, with short-term cover used to protect the other cars in the interim. For example, if you have one car that needs to be insured from February and another in June, the February car will be insured first but the policy will actually renew in June when both cars are covered. After the last car has been insured for a full 12 months, the policy will renew each year until you choose another policy.
Widespread use of the motor car began after the First World War in urban areas. Cars were relatively fast and dangerous by that stage, yet there was still no compulsory form of car insurance anywhere in the world. This meant that injured victims would seldom get any compensation in an accident, and drivers often faced considerable costs for damage to their car and property.