A personalised registration plate can be worth more than the car that carries it.

But just 6% of car insurance policies specifically cover the cost of a private number plate if the vehicle is written off or stolen.

That's according to insurance price comparison website GoCompare which has urged owners of personalised registration plates to act quickly.

Personalised registration numbers from the DVLA start at £250 and can fetch up to hundreds of thousands of pounds. In 2016-17 the DVLA reportedly sold 374,968 personalised plates.

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But a study of 302 comprehensive car insurance policies revealed that only 19 specifically covered the loss of a personalised plate, if the car was lost or stolen.

Of those providing cover, the payout varied from £200 to an unlimited amount while just 16 insurers covered a financial loss of £5,000 or more.

When an insurance claim is made for the cost of a car, the insurer owns BOTH the vehicle and the registration number assigned to it. This also applies to personalised plates.

The claimant can repurchase the registration number from the insurer, if it still owns it, for no more than the settlement price.

But, if the vehicle has already been scrapped by the insurer, then all rights to the registration plate go with the vehicle.

If a car with a personalised plate is stolen and not recovered, its owner will have to wait 12 months to get the number plate back. To reclaim the personalised plate, they will also have to prove that the car had a valid MOT and tax at the time of theft.

Similarly, motorists who have had a car with a personalised number plate written-off have to arrange for the number to be transferred to another vehicle or retained on a certificate in sufficient time before the claim is settled.

Final day of a 3-day registration plate auction event at Mercedes-Benz World

Registration numbers move with the vehicle they are assigned to, not the person who bought it. So, if the vehicle is written off and the car scrapped - the number plate can disappear with it.

The policyholder will need to contact the DVLA and their insurer to let them know that they want to keep the plate. The insurer will then write a letter of non-interest and send it to the DVLA. The registered keeper will have to pay a retention fee to keep the plate if they don’t have another vehicle to transfer it to.

Matt Oliver from GoCompare Car Insurance said: "When you register a personalised plate to a vehicle you need to tell your insurer immediately, otherwise your policy could be invalidated and, particularly if you’ve paid a lot for a registration number, you should consider whether it’s properly insured.

"A registration number is attached to the vehicle it is assigned to, not the person who purchased it. So, if you want to retain ownership of a cherished number plate you need to make sure your insurer knows, in the event of the car being stolen or written-off, you want to keep it."