If a vehicle is to be "laid up" for whatever reason, a Statutory Off Road Notification (SORN) must be submitted to the DVLA to declare that the vehicle is off the public roads and will not return to them unless the SORN is cancelled by the vehicle's owner. Once a vehicle has been declared 'SORN' then the legal requirement to insure it ceases, although many vehicle owners may desire to maintain cover for loss of or damage to the vehicle while it is off the road. A vehicle that is then to be put back on the road must be subject to a new application for VED and be insured. Part of the VED application requires an electronic check of the MID, in this way the lawful presence of a vehicle on the road for both VED and insurance purposes is reinforced. It follows that the only circumstances in which a vehicle can have no insurance is if it has a valid SORN; was exempted from SORN (as untaxed on or before 31 October 1998 and has had no tax or SORN activity since); is recorded as 'stolen and not recovered' by the Police; is between registered keepers; or is scrapped.
Auto insurance is financial protection, and not just for the investment you made when you bought your car. After a really serious accident, bills for damage and injuries can easily reach into hundreds of thousands of dollars. If you happen to cause such a wreck, the victims could sue you. In the worst case scenario, assets such as your savings and home could be seized.