As Ethel rightly says, �fronting� is well known to insurers. This is what it could mean to you:
Firstly, when you make the proposal to add your daughter�s car to your policy you will be asked if the car belongs to you. You will have to say �yes� because if you do not your proposal will simply be rejected. So you will have two cars, both (as far as your insurers are concerned) belonging to you.
If your daughter is unfortunate enough to have an accident which results in an insurance pay-out, the insurers are likely to make enquiries about the second car�s ownership. (They will see that �fronting� may be a possibility). They will be extensive and intrusive enquiries. If their conclusion is that the car is not actually yours but your daughter�s they will invalidate your policy retrospectively on the grounds that you made a false declaration to them. I�ve seen it done.
This will mean that you will be liable to pay for any damage or injuries caused and your daughter may face a charge of driving without insurance. The minimum penalty for this is six penalty points. As a result, if she has held her full licence for less than two years it will be revoked by the DVLA and she will revert to provisional status.
Furthermore if it can be proved that you had been driving since the false declaration was made you too could be charged with the same offence, or the CPS may content itself with a charge of allowing the second car to be driven uninsured. This will mean six points for you too.
I believe you can do what you want to do by means of a fleet policy. The way you are proposing is perilous and the loss of your NCB will be the least of your worries. You must decide whether the potential saving is worth the risk.