Are LED lights legal inside cars?

No, it is not illegal to drive with your interior lights on as there's no legislation mandating whether people can, or cannot, legally drive with interior lighting. Please do know that by driving with interior lights, you are making it much harder to see outside and it may be a distraction to other drivers. 

Radiant Car Lights advise you to:

Drive without interior lighting on for your safety. We are not responsible for any injuries related to our products. 

Please only have the lights on when you are at a complete stop with out any surrounding cars or pedestrians near you.

Radiant Car Lights are only suitable for interiors. Do not append lights on the exterior of your car.

Do not drive with the car lights on.