Under section 143(1)(a) RTA 1988 "a person must not use a motor vehicle on a road or other public place unless there is in force in relation to the use of that vehicle by that person a policy of insurance ."
Under section 145 the policy must be issued by an authorised insurer and must insure for death or bodily injury to any person, or damage to property, caused by, or arising out of, the use of a vehicle on a road in Great Britain, i.e. third party insurance.
A statutory defence is provided by section 143(3) RTA in relation to a driver who unwittingly drives his employer's uninsured vehicle.
The term "road" is defined at section 142 of the Road Traffic Regulation Act 1984 as any length of highway or other road to which the public has access and includes bridges over which a road passes. The Concise Oxford Dictionary defines "road" as a line of communication for use of foot passengers and vehicles; while in Oxford -v- Austin  RTR 416 it was said to be a definable right of way between two points.
The expression 'on a road or other public place' is employed frequently in Road Traffic legislation, for example, in the drafting of moving traffic offences at sections 1-6 RTA. A public place is a place to which the public, or part thereof, have access.