Police take a breathalyzer sample from a driver. (CBC)

The B.C. government will not have to pay back fines and fees to people convicted under an unconstitutional impaired driving law, the B.C. Supreme Court has ruled.

At least 15,000 people were fined and penalized for blowing over .08 while the law was in place, paying about $4,500 each in fines and fees.

But on Thursday Justice Jon Sigurdson rejected the argument that the fines were collected under an invalid law "enacted in bad faith" and should be refunded "on the principle of unjust enrichment."

Sigurdson ruled the government "did not engage in any misconduct or bad faith actions" when it enacted the law.

"I have found that the doctrine of qualified immunity provides a complete defence to both of these claims," wrote Sigurdson.

Furthermore Sigurdson ruled that anyone with any outstanding fees, penalties and suspensions would still have to serve or pay them.

Angry B.C. drivers filed a flurry of lawsuits seeking reimbursement of thousands of dollars in fines and fees, after Justice Sigurdson struck down parts of the legislation as unconstitutional, last November.

The November ruling found 90-day suspensions and costly interlock devices too harsh for an offence drivers have limited means to appeal.

The B.C. government has since passed an amended version of the law, which it says will enhance fairness for drivers accused of being impaired and increase public confidence.