Uninsured driving is a major problem and a lot of motorist who commit this offence claim that they thought that, if they were driving someone else's car, they were covered under the 'any vehicle not belonging ... etc' clause. This is true (subject to policy details) for a lot of comprehensive policies, but very few others, if any. Unrecovered losses caused by uninsured drivers are often paid for by the Motor Insurers Bureau (MIB) who claim to handle over 20,000 cases a year; and the money comes straight out of the pockets of the insurers who underwrite the scheme. The fewer non-comprehensive policies there are, the fewer claims there may be to the MIB.

In the days before MOTs and SORN many drivers owned 'old bangers' which were not worth a great deal. If they were destroyed or badly damaged, replacing them was a fairly cheap option. Those days are gone and owing to legislation and relative affluence the cars on the road today are in far better shape, and therefore worth more. This means that the demand for cheaper levels of insurance has fallen, considerably.

Apart from all of this, insurers are wary of motorists who are trying to cut corners, financially. A driver with pride in his or her motor is likely to be more careful with it that one who looks upon it as a disposable item. Also, someone who pays that bit extra to fully insure a car is more likely to attend to repairs and maintenance more enthusiastically than someone who is probably having to count the coppers.

In short, some of them feel that there is more likelihood of an accident involving someone who chooses not to have comprehensive cover. This means higher pay-outs, and so higher premiums.