The law requires children travelling in cars to use an appropriate car seat. Your baby must always go in their seat, including when you bring them home from the hospital.
It's illegal and also very dangerous to carry your baby in your arms in a vehicle.
The best way for your baby to travel is in a rear-facing infant car seat on the back seat, or the front passenger seat as long as it's not fitted with an airbag. The car seat is held in place by the adult safety belt.
Do not place your baby in the car seat wearing lots of thick layers.
The straps should be close to the baby and blankets put over the top of the straps.so you can remove them easily when going into warm environments. Coats or snowsuits should go on when you have arrived at your outside destination.
There is no published evidence that states how long babies should stay in a car seat when travelling. However, infant healthcare professionals, safety experts and most car manufacturers recommend that babies should not be in a car seat for longer than 2 hours at a time and they should be taken out frequently. In addition, please ensure that your baby’s head is always well supported as your baby’s neck muscles are not able to support their head unaided in the early months of life.
Child car seats: the law - GOV.UK Child car seats rules