A SORN, or statutory off road notification, is a declaration to the DVLA that a vehicle is being kept off public roads and will not be taxed or insured. It must stay parked on private land such as a drive or garage.
In one line: A SORN tells the DVLA a vehicle is off the road, so it does not need tax or insurance while declared.
How a SORN works
A SORN is made under the Vehicle Excise and Registration Act 1994 when a keeper takes a vehicle off the road, for repair, storage or because it is unused. Once declared, the vehicle cannot be driven or parked on a public road.
A SORN is free to make and lasts until the vehicle is taxed again. For example, a keeper laying up a classic car over winter declares a SORN, stops the direct debit for tax, and may receive a refund for any full months of tax remaining.
Driving a SORN vehicle on a public road, except to a pre-booked MOT, can trigger a fine of up to 2,500 GBP, and keeping an untaxed vehicle without a SORN brings an automatic out-of-court penalty of 80 GBP (DVLA).
SORN vs continuous insurance enforcement
A SORN exempts a vehicle from tax and from continuous insurance enforcement, which otherwise requires every registered car to be insured. Without a SORN, an uninsured vehicle on the DVLA record triggers automatic penalties even if it never moves.
A SORN is not the same as scrapping a vehicle: the registration stays live and the keeper remains responsible until the car is taxed, sold or formally destroyed.
Primary source: GOV.UK: Make a SORN