If you've got a reg on a vehicle, and you manage to write it off, you CAN still salvage the number. However, you have to be fairly quick about it. Get in touch with your insurers and confirm that they don't want the reg as part of any settlement or payout or whatever. Ask them to issue you with a letter to that effect. Your next step is to get in touch with the DVLA. Inform them that your vehicle is now in pieces but you'd like to keep the reg. They'll ask you for the letter and arrange for the registration to be transfered onto a certificate. This can take some time. Typically you're looking at 12 months before you'll be seeing your reg again.
All of this HAS to be done before the vehicle is out of your hands and sitting in a scrap yard. If you scrap a vehicle without taking a number off, then that number is scrapped along with the vehicle. There's no going back (see below for the exception). You need to remove the number (if you want to keep it) before getting rid of the car.
Many people think that if you have the V5 logbook for a vehicle then you own the mark and can do with it as you wish. That's TOTALLY INCORRECT. The reg belongs to the vehicle. Logbooks are pretty useless when it comes down to it. We get an unbelieveable number of customers who fear releasing their logbooks to us to perform transfers (obviously we need to get the registration changed on the logbook so it matches the number going onto the car). They think that as soon as it reaches us we'll immediately ask for a change of keeper and be able to waltz off with their car. Hmmm. If it was as simple as that we probably would :)
To kick off with we're an honest company, long established and not fly by night. I'm sure it would do our reputation wonders if we started pinching people's cars.
Secondly, whilst from the logbook we know where the customer lives (which we knew anyway because we ask for that info when people buy number plates from us), and hence can probably make a good guess as to where their vehicle will be located, we don't have any keys for it do we?
And thirdly, the logbook is NOT A DOCUMENT OF TITLE. That means that anyone's name on it isn't necessarily the legal owner of the vehicle. Ever bought a vehicle on hire purchase or using finance? The V5 generally stays in the name of the finance company until you've paid it off. Otherwise folks would just sign the change of owner slip and say "Ner-ner-ner-ner-ner! It's mine now! Nothing you can do!" - probably whilst dancing some kind of jig and pointing.
Anyhoo, I digress (again). The one exception to scrapping a vehicle and being able to retain the reg is if you can make the vehicle roadworthy again. If less than a year has passed since the vehicle was scrapped, you may have a SLIM chance of retrieving the number. You'd need to get the vehicle restored, taxed and tested and then apply to take the reg from it. Of course, the DVLA may turn round and simply dismiss it, or say that the reg must remain on the vehicle, or (if you're lucky) agree to transfer the number for you (either onto certificate or another vehicle).
If it's been more than 12 months since the scrapping of the vehicle, then your chances are greatly reduced. Otherwise we'd just wander into our local scrap yard, find the shell of a classic car with a brilliant plate on it, restore it to it's former glory, retrieve the reg and sell it on for HUGE sums of money. As it is, in these cases the DVLA will query if the reg is part of the original car, and that the car is indeed "original" enough. If you've only got the steering wheel and build a whole new car around it you're not going to be entitled to the reg back...